What is the part call that the oil filer screws on

That should only leak if the filter is not put on properly. The seal is on the filter itself, and if it is over-tightened, or not tightened enough it will leak. I like to put a drop of oil on my finger and run it around the rubber seal before installing it. Hand tighten then turn 1/4 - 1/2 with the proper filter tool.

I just noticed that you typed it as oil "filer", did you mean oil "filter", or oil "filler"??? If this is the tube that you're pouring the oil into, there is a rubber seal that could be bad. Usually the oil filler tubes go directly into the valve cover (which would have a plastic twist-off cap), but this would not have a seal, it is just a direct port into the cover. The other location is a long tube that goes down the side of the engine directly into the side of the oil pan itself. Those do leak over time, and it's just a rubber seal that is easy to replace by removing the screws or bolts that hold the filler tube in place, pulling it up and out of the hole in the oil pan and then pulling out the rubber seal that should still be in the hole after you pull the filler tube. The new one slides right in to place with a little oil applied to it beforehand. Put the filler tube back in, secure the fasteners and you should be good to go.

Check that the oil filter if firmly screwed onto the engine. If not then drain the oil, undo the oil filter. Wipe the surface of the oil filter connector on the engine so its clean. Get a new oil filter and smear a small amount of oil on the rubber seal. Screw the filter into place making sure it is a tight seal. Re-fill the engine with the right amount of oil. You should be good to go. Check that the oil leak is coming from the filter before you start as it could be something more serious eleswhere like the head.