Lock spreadsheet

If you're trying to protect a whole document (a spreadsheet in Numbers lingo), then you have File > Set Password... .

If you're trying to lock a table to prevent inadvertent changes, then you can click the table and go to Arrange > Lock.

Of course any user can click that table and go to Arrange > Unlock. So it doesn't provide complete protection.

SG

This is the Numbers for Mac forum. I think what you are referring to is a feature in Numbers for iOS/iPadOS that isn't a "lock" per se, but more of a display mode. The 'Edit' button to enter edit mode is still there in Numbers on my iPhone and iPad.

SG

This confused me, too. It seems to be hidden in the three-dot menu and is called "Reading View". If you open that menu (upper right) and client Reading View, the Edit you/we used to see shows in the top right.

But, be careful: even with the Edit showing, a double-click on a cell can allow changes. It's a weird situation IMO, but this is the best I can find to replicate what you/we used to use. Hope this helps.