01Step 1: choose a single photo of yourself
Use a picture where your face is sharp and your shoulders and top are in frame, and where nobody else appears. You do not need to be lying down or holding a phone, because the template supplies the pose on the bed and the receiver at your ear. A relaxed, half-smiling expression suits the chatty, unaware mood better than a serious face.
02Step 2: upload once and let it run
Put the photo in the one upload slot on the Ghostface Call page and start the image. There are no style, room or figure settings to choose. The page says it takes about a minute, and you can leave while it works; the finished 4:5 picture is saved with your other assets.
03Step 3: check both halves before posting
The joke needs two readable things: you, happily on the call, and the masked figure behind you. Open the result at full size and look at your face under the warm lamp light, then at the doorway. If either is weak, try a different, better-lit upload rather than editing the image, since the scene itself cannot be changed.