Hi!! I hope this helps.
The only way to "lock" a cell is to protect the sheet. Format your cells the
width that you want them and then click on the "Format" button on your "Home"
ribbon. It should be under "Cells". Then click on "Protect Sheet". This will
require a password.
Once you protect your spreadsheet, it cannot be changed, but you can still
edit your information.
I hope this helps!!
Good Luck!
Venetia