Drywall is a very resilient material and take a heck of a beating.
However it is not indestructible and sometimes we end up with holes from door knobs, moving of furniture and many other accidents.
Well you should be able to find a repair kit at your nearest home improvement store.
These kits are a great way to save money on hiring someone to come repair the hole as you can do it yourself and it is not to difficult.
Start out by measuring the hole in the wall then head over to the improvement store and pick up a kit that matches the size of the hole.
This kit should consist of a piece of adhesive metal lath and the putty to repair the home.
What you want to do is begin by sanding down and rough spots or cut off any paper that may be left from the hole.
Simply take the backing off the adhesive metal lath and stick it into place.
Mix up your mixture of putty and apply it to the path feathering out the edges to blend it into the existing wall.
Give this the time to dry that is on the label as provided by the manufacturer.
After it has properly dried you will want to sand down any imperfections, bumps, or grooves in the putty.
Then take a wash cloth that is very, very lightly dampened and wipe off any dust you have left on the wall.
Apply a second coat to the wall to smooth out any big divots you may have, again feathering out the edges to make sure it blends well with the existing wall.
Then repeat the drying, sanding, and wiping down process again.
Sometimes it will take a few coats to get back to smooth, but be sure not to over do it or you will end up with a hump in your wall.