In order to allow users access to RemoteApps, you can configure Web Access in three ways:
In the Setup under Sessions > RDP > Remote Desktop Web Access, configure:
Pre-Defined Configuration: Define several server connections with the same user access data. The user must enter their access data and the domain in the logon window.
Ask user: The connection is pre-configured on the server side. The user only needs to enter their corporate e-mail address.
Or select the third option:
Via browser: Access via web browser