See our Users: Overview article to understand the difference between Workspace Collaborators and App Users.
Add Collaborators to your Workspace
Click Workspace Settings
Type in the email address
Choose collaborator type Owner or Standard
Add collaborators to your apps as a user
Collaborators will automatically be added to all non-private apps, unless you have connected a user table and selected the Automatic mode. If you have selected the Automatic mode, please add the collaborators to the User table you connected.
Add collaborators to your apps as an admin
When you've added the collaborator, you might want to add them as an app admin.
Click the app you want the user to have access to
Click Manage users
Select the user in the dropdown menu
To remove a user click Edit and the x
Granting admin access for an app to a workspace collaborator you will enable them to configure the app's settings and layouts. Admin access also enables a collaborator to see and edit all data in your app—you cannot apply permissions to them.