Officially we do not support Office 365 as the automation of letters from R4 to the cloud based version of Word is non-existent, Microsoft just do not provide the same level of integration. However, if your Office 365 subscription allows, you should be able to install a desktop version of Word/Excel 2016 and that should be fine.
In relation to email, R4 does have an inbuilt email client that can be configured to use Office 365’s email servers. You will just need your account details and outlook server details. Give the team a call if you need help.