Most wreaths will come with a ribbon or attachment that'll slot onto a hook, and those that don't you can easily wrap a piece of string around yourself. The difficulty with putting one up comes if you're a renter or would rather avoid making a whole in your wall, door or mantle.
Luckily, command strips can come to the rescue. Just as they work well for hanging pictures or posters, command offer some sticky-back hooks to temporarily hold your wreath without risk to the wall. If you're wanting to hang your wreath on your door, Amazon also have some handy wreath hangers designed especially to hook over the top of your door.