Sending email from an alias using Gmail app I use G-Suite for business. I have the main domain (Let's call it example.com) and a number of secondary domains (we'll use example.co.uk for this). I have set up aliases so that I can receive email sent to joe.user@example.com and also joe.user@example.co.uk.

Using GMail on the web I can select a default email address for outgoing email. So, although my primary address is joe.user@example.com my outgoing email appears to come from joe.user@example.co.uk

So far, so good.

Now I want to do the same thing on my Android phone and tablet.

How can I set up Gmail for Android to use my alias joe.user@example.co.uk instead of my primary address joe.user@example.com?

Note that I don't want to reset the phone and sign in with a different address. I just want to change the GMail alias.

One answer to this question suggests it's not possible, but that was five years ago. Has anything changed?
It's still not possible if you use Gmail app.

Alternatively, you can use FairEmail ( link to the community ads promotion), which let's you do this and has many more features available. 

I use  Gmail aliases with this app (not affiliated to it) . You can refer to the extensive app FAQ 
in case of issues or join the active app forum on XDA