Most laptops these days have access panels on the bottom to upgrade RAM, hard drive and wi-fi card, not sure why you'd want to upgrade that last one and I've never seen them for sale but whatever! My last one you unclipped the keyboard to get to the RAM but that was actually easier. The main exception seems to be Apple who either making it massively complicated and warranty voiding or slightly complicated and possibly warranty voiding.
Make sure you get laptop RAM though, the first time I upgraded a laptop I had to take the RAM back and ask for the right sort!