Customizing tool bar and menu items
These steps are for tech savvy users. These steps are not suitable for average users.
Evolution offers no graphical interface to customize its tool bars or items in menus.
Advanced users can experiment by exploring and editing the corresponding system-wide file(s) under $PREFIX/share/evolution/ui/.
Copy those files with the file ending .ui which you would like to modify to your personal configuration folder $HOME/.config/evolution/ui/. Modify the files in your personal configuration folder so the next Evolution software update will not overwrite your changes.
The modified files will be used if the evolution-ui-version attribute of the root ui element matches the version of the default files provided by Evolution.
To change keyboard shortcuts, edit ~/.config/evolution/accels while Evolution is not running. Commented lines start with a ; character and will be ignored. Not all shortcuts can be changed though.