I use one email account for everything but I have 2 email addresses. 90% of the time I 'm happy that my normal email address shows on emails I send, but there's 10% when I want emails to appear to come from the other address. I can fix this via Tools>accounts>properties & then set "email address" and "reply address" to the alternative one. But this is a long winded way to use every time I want to do this. Is there some way that I can "Toggle " between two addresses easily?
The key is that you have to set up a separate account for each of your email addresses, even if they're with the same ISP. Then, as others have said, you'll get a drop-down menu showing each account on the Send/Receive button and other buttons.