1 - Password requirement.

When the invite file is downloaded, Citrix Director displays a popup window with a password. This password is randomly generated, and it is required for remote assistance sessions.

Admin/HelpDesk user can copy the password from Director and paste it into the Windows Remote Assistance window.

This behaviour cannot be changed, and there is no option to disable the password prompt.

2 - Windows Remote Assistance - policy / configuration:

Solicited Remote Assistance should be configured / enabled.

Please see the article: CTX696597

3 -  Windows Remote Assistance - invite file:

Access to the C:\Users\Public\Documents folder on the VDA is required. Please see the article: CTX696614