You want Copilot to automatically generate a table of contents or an index for your Word document. Copilot can create a table of contents from your headings, but it cannot generate a true index that lists specific terms and page numbers. The root cause is that Copilot works on the semantic content of your document text, not on the pagination layout that a real index requires. This article explains exactly what Copilot can and cannot do for document indexing, and provides the manual steps you must use to create a proper index in Word.
Key Takeaways: Copilot Index Limitations in Word
- Copilot can create a table of contents: It reads heading styles and generates a linked list of sections, but this is not a true index of terms and page numbers.
- Copilot cannot mark index entries: You must manually select each term, go to References > Mark Entry, and add it to the index field.
- Copilot cannot insert an index field: You must use References > Insert Index to place the final index that Word will build from your marked entries.
Why Copilot Cannot Generate a Real Index
A true index in Word is a field code that collects page numbers from marked entries in your document. Copilot operates on the content of your text using AI, not on the layout and page-break structure that Word uses to calculate page numbers. Copilot has no access to the physical pagination of your document. It sees only the words and their sequence, not where page breaks fall. Therefore, even if Copilot could identify terms to index, it cannot assign the correct page numbers because those numbers do not exist until the document is fully paginated by the Word layout engine.
Copilot can generate a table of contents because a TOC relies on heading styles, which are text-based markers. The TOC field code reads those styles and can be updated to show page numbers after pagination occurs. But an index requires explicit entry markers (XE fields) placed at each occurrence of a term. Copilot does not create XE fields, and it cannot update them. The index generation process in Word is a two-step manual workflow: mark entries, then insert the index field. Copilot cannot automate either step.
What Copilot Can Do for Document Structure
Copilot can draft a table of contents based on your headings. It can also suggest headings for sections you ask it to write. If you ask Copilot to add a table of contents, it will generate a list of headings formatted as a TOC. However, this TOC is static text, not a live Word field code. It will not update automatically when you change headings or add pages. To get a live, updatable TOC, you must use the References > Table of Contents command manually.
Steps to Create a Proper Index in Word
Because Copilot cannot generate an index, you must use Word’s built-in index tools. Follow these steps to mark entries and insert the index field.
Mark Index Entries Manually
- Select the term you want to index
Highlight a single word or phrase in your document that should appear in the index. For example, select the first occurrence of the term “Copilot.” - Open the Mark Entry dialog
Go to the References tab on the ribbon. In the Index group, click Mark Entry. The Mark Index Entry dialog appears with the selected term already filled in the Main entry field. - Configure the entry options
Leave the default settings if you want a simple page reference. For a subentry, type the subentry text in the Subentry field. For a cross-reference, select Cross-reference and type the term. Click Mark to mark only this occurrence, or click Mark All to mark every occurrence of that exact text in the document. - Close the dialog and continue
After marking, the dialog stays open so you can mark the next term immediately. Select the next term in your document, then click in the Mark Index Entry dialog to update the Main entry field. Click Mark again. Repeat until you have marked all terms. Click Close when finished.
Insert the Index Field
- Place the cursor where you want the index
Scroll to the end of your document or wherever you want the index to appear. Typically, the index is placed on a new page after the main content. - Open the Insert Index dialog
Go to the References tab. In the Index group, click Insert Index. The Index dialog opens. - Choose index format settings
Select the format from the Formats dropdown. Options include Classic, Modern, Bulleted, etc. Choose the number of columns, the right-align page numbers option, and the tab leader style. Click OK. - Update the index after editing
If you add or remove text, your page numbers may change. Right-click anywhere in the index and select Update Field. You can also press F9 after selecting the index. Word recalculates all page numbers based on the marked entries.
If Copilot Still Has Issues After the Main Fix
Copilot Returns Generic Output Instead of Tenant-Specific Data
If you ask Copilot to summarize or index content from your organization’s SharePoint or OneDrive, and it returns generic answers, the problem is likely data source permissions. Copilot for Microsoft 365 requires that the Microsoft Graph be enabled for your tenant and that the documents you want to index are stored in locations where Copilot has read access. Check the Microsoft 365 admin center under Settings > Copilot > Data sources. Ensure that the SharePoint sites and OneDrive folders containing your documents are included. Also verify that your user account has at least Read permission on those documents.
Copilot Does Not See Headings in the Document
Copilot relies on heading styles to understand document structure. If your document uses manual formatting like bold text with a larger font size instead of applying Heading 1 or Heading 2 styles, Copilot will not recognize those as headings. Apply the correct heading styles from the Home tab > Styles gallery. After applying styles, ask Copilot again to generate a table of contents or outline. The output will then reflect your actual document structure.
Index Entries Do Not Appear After Inserting the Index
If you insert the index field but see blank space or an empty list, you likely did not mark any entries. Open the index field by pressing Alt+F9 to show field codes. The field code should look like { INDEX \h “A” \c “2” }. If there are no XE fields in your document, the index will be blank. Use Find and replace to search for “XE ” to confirm that entries exist. If none are found, you must go back and mark entries manually using the steps in Section 2.
| Item | Copilot-Generated TOC | Manual Word Index |
|---|---|---|
| Method | AI reads heading styles and writes a static list | User marks XE fields, then Word builds the index field |
| Updates automatically | No, it is static text | Yes, press F9 to refresh page numbers |
| Supports subentries | No | Yes, through the Subentry field in Mark Entry |
| Supports cross-references | No | Yes, through the Cross-reference option in Mark Entry |
| Requires heading styles | Yes, must use Heading 1, Heading 2, etc | No, works on any selected text |
You now know that Copilot cannot generate a true index with page numbers and that you must use Word’s References tab to mark entries and insert the index field. For a table of contents, you can ask Copilot to create one, but for a live and updatable TOC, use References > Table of Contents. A practical next step is to open an existing document and practice marking three terms, then insert the index to see how page numbers populate. To speed up the marking process for large documents, use the Mark All button in the Mark Index Entry dialog to index every occurrence of a term at once.