I just installed elementary os Loki and I can't find an option for Google accounts or Microsoft in the online accounts menu. Is there any way I can install them? Thanks, Ben
These services aren't yet supported in Online Accounts, but they may be added in the future. From the release announcement:
The preliminary version of Online Accounts is finally landing in Loki. At the moment, Fastmail and IMAP email accounts are available with more services under development.
For now, you can log into Mail and Calendar with your Google Account. You can also add an Outlook.com account using IMAP.
Alternately, you could add both Gmail and Outlook.com as IMAP accounts in Online Accounts. Google support has details on using IMAP with Gmail.