You need to have the manager role to invite users to a workspace. Open the workspace and tap the Invite button. Enter a substring of the user's name of email address. Tap the list item with the name of the user you want to invite to the workspace. The user can accept or reject the invitation.

If a user accepts an invitation, he'll have the member role. You can change the user's role and add him to user groups in order to grant him access rights to data records. Users can decide to leave a workspace.

Before you invite a user, he must have the Flux application installed on his device. New users need to launch the application at least once in order to create a user account and be discoverable via their name or email address.