How can I fix oven door?

check the hinges ... if you set anything ON the door when it was open you may have 'sprung' a hinge --- check your owners manual, or go online to the manufacturer with type of range/model and serial # ( should be stamped on a plate on the back of the 'top' part of the range.)

Great thank you

Sounds like you might have lost the rubber seal, is it still in tact?

Is there something wrong with the gasket? I'd carefully check around the door to be sure something isn't binding it up somehow to start with.

The Gasket, sometimes called the Seal, is the tubular insulating cording that fits into the indentation surrounding the window of the oven. When the door closes, the face of the inside of the oven presses up against the gasket, making for a tight fit. A gasket that is flat, frayed, or is no longer intact, should be replaced with brand new.

Ok thank you for explaining that to me cause I think it is flat

where can I go to get new one?

Any store that sells ovens should sell them, or at least should be able to direct you to a local source.

If you prefer shopping on-line, then Amazon, eBay, and Appliance Parts.com

You're welcome. Maybe you could ask Santa to bring you a new one.