Am I able to use my identities / alias emails in outlook? I have a main account and several identities that I utilize for different emails careers@ HR@ admin@ that I want to have as separate email choices through my Outlook. I can see a drop down of my identities in RoundCube, but it won't seem to let me create the account in Outlook.
Please contact your email provider for support or search for information about using aliases in Outlook Desktop. Roundcube is a web based mail client, it is not a service. I know that Outlook does support sending from aliases (https://answers.microsoft.com/en-us/outlook_com/forum/all/sending-from-an-alias-in-outlook-365-desktop/008abc1e-af0c-49eb-ad8d-413f54f57f40) but I can't guess what rules/restrictions your email provider might have.