The best way is to pick a direction and hope that app recognizes your plan and goes along with it. If you can find their IFC tag, you can PM them, but there’s no way to tell the controller in-game what your plan is.
On expert server, all frequencies establish an ongoing communication via slack. This way they ensure to share all relevant information to the other guys.
On the ES, the ATIS also provides information for approach as to which runways have specific uses. Obviously this isn’t available on the TS, so you are stuck trying to communicate here on the forum through messaging as stated.