Which email is used

Good day all

Seems I have my first ERPNext site running !

Just going through all the settings and I am now at the email settings.
I have found a web-link explaining how to use gmail so I have set up an
email domain.
Oh, before I carry on, I did find a discussion link on this:

but the links in this thread does not exist any longer.

Anyway …
After the email domain I was wanting to set up the email accounts, but then I realized
that I do not know which of these emails are used for what.
E.g. … if I send a RFQ to a customer, then I will enter the customers email when sending
the RFQ. But which of the emails will be used to originate this mail from in ERPNExt?

I found a button called 'enable automatic linking in documents" in the email setup
page but not sure if that is the function. When I click on the help button it takes me

And then I get:
Your system is being updated. Please refresh again…

can anyone help please. I think if I have this cracked then my basic setup is complete.

Many thanks

You can assign which email addresses are available to each user in their User Settings page. Users with this defined will have a dropdown allowing them to choose from among their accounts. Otherwise, emails will be sent from the default sending address (which gets set in the email account page).

Thank you very much peterg

I shall follow your suggestions and test my emails.
I am also checking out a few other thing to see if my settings are properly done.