When you use Copilot in Outlook to draft replies or compose new messages, the generated text may not match your personal tone or style. You might see formal language when you prefer a concise or direct approach. This happens because Copilot uses a generic base model that does not automatically learn your writing patterns. This article explains how to provide personal writing samples to train Copilot in Outlook so your drafts sound more like you.
Providing writing samples gives Copilot reference text that reflects your vocabulary, sentence structure, and preferred level of formality. The process involves selecting existing emails or composing example messages and storing them in a location that Copilot can access. Once the samples are available, Copilot uses them as grounding data to adjust its output. This guide covers the required Microsoft 365 licenses, the storage setup, and the exact steps to supply your personal writing samples.
By the end of this article, you will know how to select appropriate sample emails, where to store them, and how to reference them in your Copilot prompts. You will also learn what types of writing samples work best and which limitations to expect.
Key Takeaways: Training Copilot in Outlook with Your Own Writing
- OneDrive or SharePoint storage: Store your personal writing samples in a folder that Copilot can index, such as your OneDrive Documents folder or a SharePoint document library.
- Copilot for Microsoft 365 license: Required for Copilot to access your personal files and use them as grounding data when drafting in Outlook.
- Prompt reference syntax: Include a phrase like “Based on my writing samples in the folder named MyStyle” in your Outlook Copilot prompt to activate personalization.
How Copilot in Outlook Uses Personal Writing Samples
Copilot in Outlook generates draft replies and new messages using large language models that are not pre-trained on your individual writing style. By default, the output reflects a neutral, professional tone. To make the generated text match your personal voice, you must supply examples of your own writing. Copilot can then analyze those examples and apply similar patterns to new drafts.
The feature that enables this is called grounded data retrieval. Copilot accesses files stored in your Microsoft Graph, which includes emails in your mailbox and documents in your OneDrive or SharePoint. When you include a reference to a specific file or folder in your prompt, Copilot reads that content and uses it as context for the generated response. This is not a training process that updates the base model. Instead, Copilot treats your writing samples as temporary context for the current session.
Prerequisites for Using Personal Writing Samples
Before you begin, confirm that you meet these requirements:
- A Copilot for Microsoft 365 license assigned to your account. Copilot Pro does not include access to your Microsoft Graph data for grounding.
- Outlook for Windows, Outlook on the web, or Outlook for Mac with the Copilot sidebar enabled.
- A collection of at least three to five email messages or documents that you wrote. These should be recent and reflect your typical tone.
- The writing samples must be stored in a location that Copilot can index, such as your OneDrive Documents folder or a SharePoint document library where you have edit permissions.
Steps to Provide Personal Writing Samples to Copilot in Outlook
Follow these steps to prepare your writing samples and instruct Copilot to use them when drafting messages.
- Select your best writing samples
Open your Sent Items folder in Outlook. Choose three to five email messages that you composed and that represent your natural writing style. Look for messages where the tone, sentence length, and vocabulary match how you want Copilot to write. Avoid messages that contain confidential data or personal information you do not want Copilot to read. Copy the text of each sample into a separate Word document or plain text file. - Save the samples to OneDrive or SharePoint
Create a new folder named MyStyle or something similar in your OneDrive Documents folder. Save each writing sample file into that folder. Use descriptive file names such as SalesReplySample.docx or ClientFollowUp.txt. If you work on a team, you can store the folder in a SharePoint document library that you own. Copilot can access files in both locations as long as you have the correct license. - Open Outlook and start a new draft
In Outlook, select New Email or reply to an existing message. Click the Copilot icon in the ribbon or the Copilot sidebar to open the drafting pane. Type your prompt as you normally would, for example “Draft a reply thanking the client for their feedback.” - Add a reference to your writing samples in the prompt
Extend your prompt with a phrase that tells Copilot where to find your samples. Write: “Based on my writing samples in the folder named MyStyle in my OneDrive.” You can also reference a specific file: “Use the tone and style from the file SalesReplySample.docx in my OneDrive.” Copilot reads the content of those files and adjusts the generated draft accordingly. - Review and refine the generated draft
Copilot produces a draft that attempts to match your samples. Read the draft carefully. If the tone is still not right, adjust your prompt. You can add more specific instructions such as “Keep sentences under 20 words” or “Use a casual tone with contractions.” You can also replace the sample file with a better example and repeat the prompt.
Alternative Method: Use a Saved Prompt Template
If you frequently use the same writing samples, you can save a prompt template in a Word document or in the Copilot Lab. Write the full prompt including the file reference, then copy and paste it each time you need to use Copilot in Outlook. This saves time and ensures consistency.
Common Mistakes and Limitations When Training Copilot with Writing Samples
Even when you provide writing samples, Copilot may not perfectly replicate your style on the first attempt. Understanding the common pitfalls helps you get better results faster.
Copilot Ignores the Writing Samples
If Copilot produces a draft that does not reflect your samples, the most likely cause is that the file reference in your prompt is ambiguous. Make sure the folder name or file name is exact. Use the full path when possible, for example “MyStyle folder in OneDrive Documents.” Also confirm that the file is saved in a location Copilot can access. Files stored on your local hard drive or in a non-indexed folder are not reachable.
Writing Samples Contain Mixed Styles
If your samples include both formal and casual messages, Copilot may produce inconsistent output. Select samples that share a consistent tone. For example, if you want casual replies, use only casual emails. If you need formal client communication, use only formal samples. Keeping the samples uniform helps Copilot identify the correct pattern.
Copilot Returns Generic Output Instead of Tenant-Specific Data
When Copilot cannot find your file, it falls back to its default model and produces generic text. Verify that your Copilot for Microsoft 365 license is active and that you are signed in with the correct account. Open your OneDrive in a browser and confirm the file exists in the folder you referenced. If the file is in SharePoint, ensure you have at least read access to the document library.
Writing Samples Are Too Short
A single sentence or a very short email does not give Copilot enough context. Each sample should be at least three to five sentences long. Longer samples that include greetings, body text, and closings produce better results because Copilot can learn the full structure of your messages.
Copilot in Outlook: Default vs Personalized Drafting
| Item | Default Copilot Drafting | Personalized with Writing Samples |
|---|---|---|
| Output tone | Neutral and formal | Matches your sample tone |
| Sentence length | Average 20-25 words | Based on your typical length |
| Vocabulary | Generic business terms | Words and phrases you use |
| Setup required | None | Select and store 3-5 samples |
| License needed | Copilot for Microsoft 365 | Copilot for Microsoft 365 |
| Prompt modification | No extra text needed | Add file reference to prompt |
| Consistency across sessions | Same output each time | Depends on samples used |
The table shows that personalization requires additional upfront work but yields drafts that sound more like you. The default method is faster but produces generic text. Choose the approach based on how much control you need over tone and style.
You now know how to train Copilot in Outlook by providing personal writing samples stored in OneDrive or SharePoint. Start by selecting three to five of your best emails and saving them as text files. Use the prompt reference syntax to direct Copilot to those files each time you draft a message. If the output does not match your style, refine your samples or add more specific tone instructions to your prompt. For advanced control, experiment with the “Compose by Copilot” feature in Outlook that lets you adjust tone and length before generating the draft.