Requirements for chat with external user

[a___r1180]

I have a problem with finding information what are the requirements for an external user to contact our employees through Microsoft Teams. We use the link: https://teams.microsoft.com/l/chat/0/0?users=employee_email. It kind of works (I've tested it on one external account), but I do not know when it might not work and what to do then.  (We do not invite guest users. External users should be able to contact their salesmen through that link).

What kind of account is needed for that kind of chat: "Microsoft Account"/"Teams Account" or no account (I've read you don't need an account to join a meeting) or maybe something named differently?

Now after clicking that link you have to click a tiny link on the bottom of Teams window: "Continue your conversation here". Is it possible to eliminate that step?

[#2]

@a___r1180 

Hi, the ability to chat with an external user is all down to your Org-wide settings in the Teams admin center as shown below.

You can view more information at - https://docs.microsoft.com/en-us/microsoftteams/manage-external-access 

[#3]

@PeterRising I have read this site but it doesn't give me an answer. That's probably already set up right because I could start conversation from an external account. I need to know what are the requirements on the other side. Is it Teams Account or Microsoft Account? I would like to give users some information.

If I understand well the other company has to have "Users can communicate with other Skype for Business and Teams users" turned on?

[#4]

Yes, both sides will need this turned on in order for this to work.