Multiple Accounts on a cell phone

Friends,

I have a question for the community: How do you deal with multiple email addresses on your cell phone? For example, I have my main address under my domain christian-gaeng.de. I also have an Outlook address and a Gmail address. I like to use the GMail calendar because it is very precise and convenient when entering the address for an appointment.

I know you can have email addresses forwarded. But that is not always reliable and I am always unsure whether I should leave a copy on the email server or not. Sometimes forwarded emails have not arrived.

How do you do that?