[JPedro]

https://sampwiki.blast.hk/wiki/SetObjectMaterialText
https://sampwiki.blast.hk/wiki/AttachObjectToVehicle

Seria algo assim:

PHP код:

new objectid = CreateObject(19353, 0, 0, 10, 0.0, 0.0, 90.0); //create the object
new vehicleid = GetPlayerVehicleID(playerid);
AttachObjectToVehicle(objectid, vehicleid, 0.0, 0.0, 1.0, 0.0, 0.0, 0.0);
SetObjectMaterialText(objectid, "SEU TEXTO AQUI", 0, OBJECT_MATERIAL_SIZE_256x128,"Arial", 28, 0, 0xFFFF8200, 0xFF000000, OBJECT_MATERIAL_TEXT_ALIGN_CENTER);