Microsoft provides instructions showing how a non-staff member can join a meeting from Microsoft Teams. Instructions will vary somewhat depending on the type of device an individual is using. Teams meetings can be joined from computers or mobile devices, and do not require creating a Microsoft account. Generally speaking, external users will use the "Join by link" option as described in Microsoft's help articles below.
Instructions for Joining by Link on a Computer
Instructions for Joining by Link on Mobile
Joining a Teams Meeting Example Video
This article shows you what a non-staff member will need to do to join a meeting with you in Microsoft Teams. If you're looking to learn how to invite a non-staff member to a Teams meeting, view our instructions here.