The door has swelled due to excess moisture being absorbed into the wood. The bath fan is absent or not on long enough and/or the door tops and bottoms have never been painted to keep the moisture out.
Two options are available.
1. Cut the door so it fits correctly at this time. Then paint all the sides of the door.
2. Wait until December when the heat is on and the door dries out and shrinks. Then paint all sides of the door to keep it from swelling this time next year.
Ron

You may be able to adjust it, see where it is binding. Sometimes you can adjust a door by taking a longer screw and pulling the door casing into the stud. Remove a screw from the hinge and use that opening to put in a longer screw. Remove a screw that is farthest from the door to ensure that you hit a stud. If its a small area that is binding you can also sand that area on the door to eliminate the binding. Prime the bare wood after its sanded.

I'm the lady with the door problem. Thanks so much for your help. I tried the sand paper first and it worked. I need to know if I can seal the part I sand with varnish or what kind of paint to keep the moistrue out? These is no fan in in hall bathroom.

Thank you so much for helping me.

yes you can use varnish. remember that the varnish will add thickness so sand enough to accommodate the varnish. A little extra sanding will take care of it.