The locate command can be used to find files by name.
As usual you can find out everything you could possibly want to know about the the locate command in the manual pages.
Essentially, locate, at set periods runs a cron job indexing each file name into a database. The locate command simply searches the database for a given file name. If you know the file you are searching for is new, you might first need to update the locate database with
In its simplest form, to find a file called myfile.txt, run.