My audi hit something and put a hole in the oil pan, i replaced the oil pan and oil and a guy say my main insert needs to be replace or swap the engine im wondering what is the main insert and should i replace the engine.

If oil pan is bend you need to take the dent out or replace it because your connecting road is kicking and gets stock
If after you fix that the noise still there you might run it with low oil and connecting road is doing the noise

Your hole in the oil pan is from some damage caused when the vehicle hit something over rough terrain, I am assuming since it is a 4x4. The mixture of water and oil is because you have some leak whether it is a blown gasket or maybe some hole internally in the engine. Do you notice a brownish foam at the end of the oil dipstick if you check the oil, that is usually a sign that water is seeping into the oil parts of the engine.

unfortunately theres no way to prove where the damage was done. maybe you can work something out with the garage to get you a cheap oil pan

Could be a broken oil pressure sending line or something worse.... Hole in oil pan, broken/missing (blown-off) oil filter.

You can remove the instrument cluster and remove the light bulb.

Try again use silicon sealant where needed eg ends of rubber All bolt holes in pan need to be "peaned" back (hit with ball hammer) Watch torque settings. Often too tight splits gasket. Clean Dry surface = no oil
Make sure it's not the main seal leaking !

You probably put a hole in your oil pan. It has to be removed, cleaned, and patch the hole. Make sure you have a fresh gasket and silicone when you replace the pan. Your local auto parts store can give you some tips for the job.

sometimes vehicles are equipped with an inertia switch wich means that when you hit something or the car has a big impact, that switch will shut off the fuel pump...

i know for a fact that on ford models they are located in the trunk on the right side...

you should check for that first and if you have one just press the button to reset...

Audi used a sealant and when i do this job I bang a scrwdriver in between the block and the oil pan and prize it off.

You most likely hit a curb, the pan is cast aluminum and will break like glass if you hit a curb, the pan can be changed without removing the engine, it is very time consuming, but it can be done.