What is a one-sentence summary of the following article?
If you aren't signed in to your Google account, follow the on-screen instructions to do so now.  It's at the top-left corner of Sheets.  By default, the file will retain the same name, though the words “Copy of” will be added to its beginning. Changing this title is optional. To do this, click the drop-down menu under “Folder” and select your desired location. You have now saved a copy of this file to a folder on your Google Drive.

Summary:
Navigate to https://sheets.google.com in a web browser. Click the sheet you want to save. Click the File menu. Click Make a copy…. Type a name for the file. Select a Google Drive folder. Click OK.