Some Creality machines have press-fit extruder gears. These usually pull right off with standard pliers but adding some WD-40 to the top of the gear/shaft and letting it set up for 5 minutes will usually loosen it up quickly. Make sure to clean off the WD-40 before installing the new gear.
If you do not want to try pulling off with pliers you can use a small bearing puller like this one.
Thank you to Dravik on our Discord for sending in the below pic and letting us know that this is a new thing Creality is doing on some printers now.