Use terminal maps to plan your drop-off or pick-up point; some ride-hailing apps designate specific zones

https://www.scribd.com/document/1074929924/National-Rail-to-Heathrow-Routes-Transfers-and-Tickets-Explained-232993

Use terminal maps to plan your drop-off or pick-up point; some ride-hailing apps designate specific zones, and short-stay car parks are signed clearly.