A friend is someone who can be male and female. There are some friends who can be close, and there are also some that are acquaintances. Friends are people that you can share your life with, but the relationship will be platonic.
Your relationship will be on a different level because you would like to just share a few laughs and have a different type of relationship with another person. A girlfriend is someone whom you can have a romantic relationship with. A girlfriend is someone that you can possibly share your life with for a long time, depending on how compatible you are and how in love you are with each other.