Adding an icon to main toolbar

[Tony Vella 2]

I am at the very beginning of a language course and at 70 years of age my most used action is "undo".  I was wondering if instead of going repeatedly to the edit menu I can just add an "undo" icon to my main toolbar?

 

Thanks is advance for all help.

[gazumped 11,664]

Congratulations - you're older than me.  Just.  Not sure that you need an icon though - have you tried Ctrl-Z?  (Press and hold Control and tap the 'z' key)  That should unwind whatever is was you just deleted or mistyped...