"
"It’s fair to say that providing a direct chat link to the whole world isn’t everyone’s idea of a good thing, and not everyone will be comfortable doing it. Depending on your role, your company might not even allow you to do this even if you want to.
The good news is that people external to your company will only be able to use this link if your Teams admins have allowed external guests to chat with people inside your company. If they haven’t, this link won’t work."
Creating the link is surprisingly simple. Take the following URL and replace <user1> with the email address you use in Teams:
https://teams.microsoft.com/l/chat/0/0?users=<user1>
So, if your email address is “sam@example.com,” the link would be:
https://teams.microsoft.com/l/chat/0/0?users=sam@example.com
You can now head into your email client of choice and add the link to your email signature.
Whether you only opt to use this internally or decide to keep your Microsoft Teams open to external guests, people can now just click a link to DM you.