Changing from PC to Mac - auto adjusting row height / column width with shortcuts - [alt] O (format) "R" (Row Height) "A" (autoset) - Are there similar function strings for MAC based Excel please ?

What Jazlyn Xu wrote isn't exactly correct. There is a similar capability on a Mac but it's more convoluted than on a Windows PC... So much so that most users never bother with it. E.x., for the AutoFit command you alluded to you would have to:

1. Press Control+F2 to access the menu bar
2. Type fo to select the Format menu (or repeatedly press Tab)
3. Press ↓ to get to AutoFit
4. Press return to execute the command

It's far easier to create a keyboard shortcut to directly execute the command. In System Preferences - Keyboard Shortcuts select App Shortcuts in the left column then click the + button & choose Microsoft Excel from the list of programs, then;

1. Type this exact string into the Menu Title field: Format->Row->AutoFit
2. In the Keyboard Shortcut field press the key combination you want to assign
3. Click Add

It's best to determine a combination which ios not already assigned unless you're sure you want to reassign it. Also, not all combinations can be used... just try another.

You also will find a Row Height command in the Customize Keyboard dialog but it actually hides the row rather than adjusting the height.