To open the gas tank on a 2021 Acura RDX, first shut off the engine and unlock the driver’s side door using the master door lock switch. Then exit your vehicle and push on the right hand side (closer to the rear bumper), and the fuel fill door should pop open.
From there, place the nozzle of the gas pump into the fuel tank and fuel as normal.
After the filler turns off automatically, wait about five seconds before removing the nozzle to ensure that any excess gasoline doesn’t spill out. Once the nozzle is removed, you can shut the fuel door by hand.