Excel Spreadsheets

A decade ago, Rdale wrote here: Spreadsheets for Time & Expense Ttracking

that:

Blockquote but if you check your settings, there’s a check-box for allowing it to import non-supported documents

Where is this setting?

Does not exist and is not needed in the current version of Scrivener. Just import the file(s). Note that non-text files like spreadsheets cannot be imported into the Draft folder.