To be able to add a new employee on Paymash, you need to have admin rights.
Log in to https://app.mypaymash.com/ and go to "Employees". Click on the blue plus sign in the top right corner. Enter first name and optionally last name. Upload a picture of the employee, this will provide a convenient login screen on the POS.
Determine which rights your employee should have.
Finally click on "Save".
Learn more: Granting access rights to employees