Fitted clothing. Shorts, plus a sports bra or no shirt. Bare feet. Full body in frame from head to feet. Camera at hip height, about ten feet back, phone propped rather than handheld. Plain wall, even lighting, no backlight from a window.
Stand the way you normally stand. Do not correct your posture for the photo, since the way you naturally stand is the thing being reviewed.
Send standard photos, not ProRAW or 48MP, so each file stays under 10 MB.