If you have clicked on a race signup link and cannot edit the sheet, please go to the 2023 Racing Calendar page on MBYC.org and try to click on an upcoming race from there.
If you want to know why this happening - read below.
It's likely that you are on an iPhone and Google Sheets Mobile App and are experiencing a bug where links from one Google Sheet to another Google Sheet force you into view only mode.
If you click on a link to a sheet from a normal web page (as opposed to clicking from inside of Google Sheets Mobile App) then the bug doesn't happen.