How to create formula that extract user assigned?

[SoMedia]

Hi
I have a base with a column for User.

I want to build a formula that extracts the user email of the User assigned and shows it in a new column.

How can I make it?

[TheTimeSavingCo]

I don't think you can do this with a formula and would need an automation for this I'm afraid.  Here's how you could set up your Update Record action to grab the email:

Link to base