Can you Customize the Outlook Client Ribbon

Hi All,

Just a quick question as I am a bit of a outlook client customization noob.

Is it possible to customize the Outlook 2013 client ribbon as I need to add some warnings to do with export compliance. If not what are the other suggested approaches but it has to be in outlook and not CRM as I have the warnings in CRM itself already covered!!

Any help would be great.

Thanks in advance...