What should go in a product changelog entry?

A good changelog entry answers three questions for the reader: what changed, why it matters, and what to do next. Structure: a short title (one line, starts with a verb — "Added export to CSV"), 1-3 sentences of context (the problem it solves, not the implementation detail), a screenshot or GIF if the change is visual, and a link to documentation or the feature itself. Group entries by type (New, Improved, Fixed). Keep technical entries separate from user-facing ones. Date every entry. The mistake teams make is writing changelogs for themselves — commit-message style. Users don't care which ticket you closed; they care what's different when they log in tomorrow.