Can you make a 18 year old daughter leave your house. Can I change the locks on the house doors?

Changing the locks on the doors is a little harsh. Has all else failed? Of course you can change the locks on your house doors and lock her out. This could create a life long rift in your relationship. If you can afford to pay first and last month's rent. Offer that. If she refuses, then change the locks. You have done what you could to prevent the lifelong rift while ending an impossible situation.