It's a loaded question. Depends on the make and model vehicle. On some cars, the manufacturer force you to remove the lower dust shield which may be time consuming ... other makes, like VW force you to replace the filter element in an oil canister.
For me it's extremely easy ... for first timers it may be considered dirty and messy. You'll need a jack stand (or a drive up stand to get clearance under the car), a plastic oil 5 quart oil pan to hold your dirty oil, a 2 gallon container to hold the dirty oil, an oil filter wrench, a long box wrench to torque off the oil pan bolt, paper towels and throw away rubber gloves.
Go to any retail auto establishment to help you get set up with the basic tools and equipment.