When opening a link to a Citrix site the Edge browser prompts the user before opening the Citrix Workspace app.

The prompt can be disabled by configuring the group policy below:

User Configuration -> Policies -> Administrative Templates -> Microsoft Edge -> Define a list of protocols that can launch an external application from listed origins without prompting the user.

Add the following string for the policy above:

[ { "allowed_origins": [ "https://siteurl" ], "protocol": "receiver" } ]

Then Edge will not prompt when accessing that site before opening Citrix Workspace.