We're in the process of creating a website through Square but, we have hit a wall when addin new Employees, we've failed to locate a way to do so.
Not sure if you're asking about adding a new employee via teams, so they have permissions or if you're wanting an employee to manage your website.
Some info on setting up employees...
https://squareup.com/help/us/en/article/5591-get-started-with-employee-management
https://squareup.com/help/us/en/article/6455-setting-up-your-employees-with-square-for-retail
https://www.youtube.com/watch?v=9uE_pY7HRBE&t=53s
https://www.youtube.com/watch?v=aXXDqYWYlTk
You should be able to set access to your online store through teams.
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