mail.app
I've reinstalled my dad's MacBook Air and now, for some reason,
we can see the postal address next to name and surname in Mail.
I've attached a photo.
As you can see, the photo shows a random email sent to us displaying
name and surname like it should, but also the postal address. How can I disable it so the postal address is not shown?
What is shown in the top part of the Mail app can be customised
Click on the box I highlighted and choose Customise. You will get a list of fields to show.
One of them is the From fields which is the one you want. Strictly with well behaved mail clients and users the Reply-To is really more relevant as that is the one a reply will be sent to However I find that some correspondants don't use it - I don't know why.
That line is added by the machine that received the mail from your Mac, so you don't get to control that from Mail.app or macOS.
This is very intentional, so unless your mail company wants to be taking responsibility for all the mails you send them, they might not be willing to "own" the mails you ask them to forward.
The machine that received the mail already knows the IP address and what it thinks is your host name so you would open a ticket with the team that manages that server if you needed to change the source of your mails or alter that header content in any way.
Best Answer
That is a Junk mail.
What they put in the TO field you can not change.
Somehow they have your Dads address in they records and put it in the TO field for some obscure reason.
However if you wish not to see emails like that then
Select that email
Click on Mail (top left)
then Preferences
and select rules
Now set it up as shown, and emails from CheapOAir will be Automatically deleted. You can undo this if you want to see them again.