What can be causing the engine to knock?

It's a Ford Explorer 06 v6 4.0 engine with 94965.2 miles on it. I mainly use it for work I do the oil changes on time I use mobile one 10w 30. Should I still be using the same oil or could this be a different problem? It runs great really smooth don't have any leaks I don't understand why the knock let me know what you guys think.

It may be the heater. Same problem in my 2016 Hyundai Tucson. (sorry if I spelled Hyundai wrong)

You may be o.k. - The modern cars have hydraulic valve lifters. When the car is cold and the oil is viscous, the hydraulic lifters may be slow to remove the valve tappet clearance. After the car warms up and the valve lifters adjust, the tapping goes away. This may be what you are experiencing.

5-30 is way too thin for 94K you need at least 5-40 or 10-40 even 10-50

Could be a loose motor mount.
it could be locking up= oil switch could be an issue
shop will be able to give you the answer on diagnostic machine in a matter of minutes

There are many kinds of knock. When does it knock? Does the knocking increase when you rev the engine?
Does it knock only when accelerating? Does it knock only when cold? Please tell us more so we can have a better understanding of the problem.

Is the issue oil and wear have drained away it's guts.

It wants to come in

Had something like with our '79 Chev van. Technician said he just put a gas additive that cleaned out the carbon build-up at the top of the piston. That was 30 plus years ago; now I would use quality synthetic and quality gasoline additive on a regular basis.

Bad crank bearing, sell it before it blows up.

A true engine "knock" is related to connecting rod bearings. If the ignition timing is too high (too far "advanced"), a perfectly healthy engine can knock.

Other causes are usually due to some kind of mechanical damage and may not be changeable without replacing engine parts.

If oil pressure is low or zero, there will be noise and damage.

Excessive wear on soft connecting rod bearings can make noise.

Other things in an engine can make a noise, that the inexperienced will call a knock, but really isn't. Slop in a hydraulic liftered valve train makes a loud noise too, but more of a "clacking" sound.

Best is if you bring your car to a seasoned mechanic with an experienced ear, and get an initial opinion.