Generally, one can love a lot of people. One can love family, friends, animals, etc. To fall in love is used to describe when someone starts to romantically love another person. "Hey mom, I love you" "I love you too, son." "I met this girl for a date last night. She is so great, I think I have fallen in love with her"

An example of use: I fell in love with my wife forty years ago, and I have loved her ever since.

Falling in love with someone is a 'period' early on in the relationship when you begin to notice you have strong feelings for the person.... Friends -> Falling in Love -> Love