Remote software for MBP

Hey guys, I just wanted to ask if anyone knows if there's remote software that's built-in to Yosamite. I want to be able to remote into my cousins MBP to help her out. She has a new MBP and I upgraded her OS to Yosamite and I have the same OS on my MBP and iMac. If so, where is it and how hard is it to use it? If not is there a freeware remote software that we could use? Thanks everyone!!

There is this option:
OS X Yosemite: Allow access using Remote Desktop

Or you can try TeamViewer. It is free for single use and absolutely the best. I use it to remote into my work computer all the time. It works on mac to mac, windows to mac, or windows to windows.

TeamViewer - Free Remote Control, Remote Access & Online Meetings

Lisa