It seems that it is not possible as of the current date as replied on TFS support forum:
How to change TFS sender ID?
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09-03-2022 - |
Question
I am using TFS hosted service at visualstudio.com
I have successfully setup Alerts for my account.
I am receiving these alert emails from this ID: admin@visualstudio.com
Is it possible to change it to reflect our company name ?
Solution 2
OTHER TIPS
The Visual Studio Online update that was rolled out around 11-Dec-2013 changed the "sender" of the alert e-mails. They now appear as if they come from the most logical person, with their Visual Studio Online e-mail address.
For example, if Jane Joe changed something that would cause an alert, the alert is now coming from Jane Joe's Microsoft Account e-mail address instead of a generic admin@visualstudio.com (or other) account.
This isn't the first time Microsoft has changed the sender information in these e-mails, so no guarantee they will remain this way, but as of now that is how it works.