Filing a VFR flight plan and getting VFR flight following aren’t connected.
When you call clearance delivery and request flight following somewhere, you aren’t filing a VFR flight plan. Conversely, when you file a VFR flight plan, you aren’t in the ATC system.
When you file a flight plan, Flight Service keeps track of your info for search and rescue. If you haven’t called to close your flight plan within 30 mins of your ETA, they start calling around looking for you (kind of a hassle to have to get someone to drive around the airport looking for your airplane), so close your flight plans! ATC’s job is not to close your flight plan!!! We have to call FSS just like you do to do that, and sometimes the wait is just as long for us as it is for you.
When you get flight following, you’re given a beacon code, radar identified, and handed off from sector to sector just like an IFR airplane. That’s when you show up in FA. The difference is traffic advisories are workload permitting and the separation standards are different.
We talked about this in another thread recently, but if you get a code that starts with ‘0’, you’re on a local transponder code and won’t be on FA, and probably won’t be able to be handed off outside of the airspace of the facility that gave you the code. If your code starts with a 1-7, you’re in the NAS system, will most likely show up in FA, and can usually be handed off to the next controlling facility along the way.
My facility also uses X12345 for local VFR traffic, then N12345 for IFRs and VFR flight following aircraft. The only reason for the ‘X’ vs the ‘N’ is for quick reference to everyone else that the aircraft is VFR. It’s just a local procedure though, some places have other means of identifying VFRs vs IFRs, etc . . .