Nikon D5500 - Manual (Page 139)

115 P, S, A, and M Modes
Mode P (Programmed Auto)
This mode is recommended
for snapshots or whenever
you want to leave the camera
in charge of shutter speed and
aperture. The camera
automatically adjusts shutter
speed and aperture for
optimal exposure in most
situations.
To take pictures in programmed auto mode, rotate the mode
dial to P.
Mode dial