Turn off the drill and unplug it or remove the battery
Hold the drill firmly
Open the chuck by turning it counterclockwise
If it is a keyless chuck, twist the chuck sleeve until the jaws loosen
If it is a keyed chuck, insert the chuck key into the hole and turn it counterclockwise
Pull the drill bit straight out
Tighten the chuck again if needed
Check that the bit is fully removed and the chuck is secure