If you click once, the tabs name will not be editable but instead, it will just open the sheet in front of you. So, to change the name of the sheet, click the cursor twice on where it is written ...

To fix the Excel file could not be found check the spelling error, try reducing the Excel file's path length and deactivating add-ins.

Locate the file in File Explorer. Click on the View tab at the top and check the File name extensions box. You should now see the .xlsx, .xls, or a similar extension at the end of your Excel file.

You can show File Path on Title Bar in Excel and Word by creating and running a Macro - and even in Quick Access Toolbar too. This post explains the process in detail.