Q: How can I collapse or expand a Doc title?

A: Hover your cursor over a title, and click the Collapse or Expand button that appears before the title.

Q: Does title collapsing or expanding action affect other users?

A: If you're the only one with permission to read the Doc, collapsing or expanding the title won’t affect other users. But if you have permission to edit the Doc, collapsing or expanding does affect other users. For example, after you collapse a title, it'll be collapsed too in the Docs interface for other users when they read this Doc.