I ve seen shims used behind the hinge leaf to adjust the gap but bending the hinge takes less time.
Shimming a door hinge to keep the door open.
When shimming the door the goal is to make sure that once the frame is nailed the gap between the door and the frame is equal all around the door.
Open the hinge side gap by spreading the hinges.
Open and close your door then let it hang freely to test whether the door is now level enough to work properly.
Sometimes the gap is far too wide.
Slip a 1 16 in thick cardboard shim strip behind each hinge photos with steps 1 and 2 below.
Self centering bits come in sizes to fit cabinet and full size door hinges.
So try this trick first.
Common problems associated with door openings require shims to be installed in the correct place to solve the issue.
Reinsert the pin tapping it gently into place from the top with your hammer.
If the problem persists repeat the process to add a second shim to the hinge.
Most pre hung doors come with a 1 8 inch gap between the door and the frame on the hinge side and the top.
Slide the shim behind the hinge that needs the extra spacing then drive the screws back in tightly and check the operation of the door.
Adjust the gap by bending the hinges.
This video will cover the basics of shim.
If it is still swinging open on its own repeat this process with the bottom hinge.
As you can see in the initial picture and video the latch was lower than the striker plate.
If the door has three hinges remove the screws from the middle hinge as well.
This job can be a hassle especially if you have painted trim.
To readjust the door frame you have to remove the trim along the latch side to get at the shims.
The solution that worked for me was to shim between the door frame and door hinge.
You can buy them at home centers or online for less than 15.