You can edit shortcuts to fit your needs by going to ... > Settings > General > Shortcuts.
Click on any shortcut that you want to change. Then, press the combination of keys you would like to use instead and the new information will appear next to the option name.

Find the full list of all shortcuts on our website: eM Client Shortcuts List

You cannot create new shortcuts in the Settings but the new Quick Actions feature allows you to create your own shortcuts and combine numerous actions into one. Shortcuts for new actions cannot be created at this time.