You don't check current draw with a voltmeter. You use the ammeter function of your meter.

Modern meters have such high impedance that just a few micro-amps current will give a false voltage reading.

Ok so I'm obviously on this forum to fix my mower. If I was an expert...I wouldn't be here. Let's pretend I never checked it with a meter. ITS STILL ON ITS 4TH BATTERY. Other than the fact that I'm not good at using the proper setting on my multimeter...does anyone else have any advice on why my mower is doing a parasitic drain on 4 batteries now,,,based on what's been replaced

Using the ampmeter, (some call it an ammeter), function
of your meter, as Mr. Kapaun has suggested, starting at
the battery, systematically move down the line and disconnect/reconnect until the current draw drops to zero. Don't jump around from this point to that point, but
move in line with current flow. Eventually you will
diconnect something and the draw will disappear and
you will have your 'AHHA' moment. Oh, and by the way,
start out with your ammeter on it's highest setting,
just in case it is a large draw. Happy hunting.

If we pretended you never used a meter, we wouldn't know you had one, thus the ability to check for current flow.

Modern meters are almost "too good" for some applications. You can probably get voltage reads just by touching the leads to the battery surface between the terminals, especially if it's an older battery with a dirty, oily film on it.

The ammeter function is used in series instead of parallel like the voltage functions.
You'll probably have a different "jack" to plug in the RED lead and a different range on the dial. Instead of V, it should be A. Used the HIGHEST range to start. That's probably either 2A or 10A, depending on the meter.

You might want to use a pair of alligator clip leads like the cheap ones from Radio Shack etc.

Likely, your draw is from the voltage regulator/charge diode at the engine.

You didn't mention ANY model numbers for the machine or engine.
If we knew that, we MIGHT be able to find an actual schematic to better look for potential trouble spots. Some schematics are readily available and some aren't.

I have 2 Troy Built lawnmowers and they both have issue with battery. My husband passed away this year so I have to call my sons to help me every single time there is a problem which gets old for both parties. Every single time I have went to cut grass this summer the battery is dead on both lawnmowers. At the beginning of summer I had them both put in the shop and had general maintenance checked on them. They came home working fine and this is the first time I used them. They crunk fine at first but the next time the grass needed cut it wouldn’t turn over. I had new battery’s put on lawnmowers and still will not crank. My husband had a jump box and it will not crank the lawnmowers. I have to charge the battery to use the lawnmowers every time even with new battery. I’m so frustrated.

Tammy other than you bring units in to determine what is draining the battery or inspect at your residence , why not disconnect the positive terminal from the battery between cuttings . Charge battery when done cutting and reconnect the terminal and go cut grass the next week . Over the winter have the mowers inspected at your leisure by a competent source .