Word table of contents missing headings: fix styles and update the whole table

In desktop Word, select the heading text in the body, then use Home > Styles. Use Heading 1 for a main section and an appropriate lower-level heading style for a subsection. Keep the hierarchy meaningful; changing every subsection to Heading 1 just to make it appear can flatten the document’s structure.

Select the table of contents, open References > Update Table, and choose Update entire table. Updating page numbers only does not add newly created sections or reflect changes to heading text. For example, after renaming a heading, use the entire-table option before checking whether the new name appears.

If main headings appear but subsections do not, open References > Table of Contents > Custom Table of Contents. Check the number of heading levels shown. Include the level used by the missing subsection, confirm the change, and inspect the resulting contents. This affects which levels are included, not the wording of the source heading.

A manual table contains entries you type yourself and cannot collect headings automatically. Save a copy before replacing a customized manual table. Insert an automatic table from References > Table of Contents, then verify the section titles and page references. If a heading is still absent, compare its actual paragraph style and level with a heading that does appear.