Your own documents and circles show up in the top search box, marked with a 🔒 so only you see them. Click the magnifying glass at the top, or press the / key, and type a name or a word.
Documents: Your documents, spreadsheets and presentations are listed in Docs, under Only you on your own profile or under You on a phone. Search results include them, but I don't have a description of a separate search box inside Docs, so if you can't find one there, please send that through Feedback.
Circles: Open Circles at the top to see the ones you belong to. Once you're inside a circle, type in the box at the top of its page to search within it. A circle's Files are searched by file name and by the words inside them.
To narrow a search, use the Any time menu beside the search button, or add a filter such as in:places.
