AC DC ? and other question for low frequency meter

So, need to learn some basics, concerning low frequency readings, not very good at all these technical things. Choice between Electric or Margnetic. Would be grateful for some hints.
- If there is are 2 you can choose from, AC and DC on the meter, which one, and why/how/when?
- If there is a choice between these 2:  199,9nt/Vm and 1999nt/Vm, which one to choose and when?
Thanks for any advice !

Also, another question:
Do I need to ground, or use some sort of cable, or could I just use the the meter in my hand, without need to plug it on/ ground it?

Well, the basics are already a lot to explain.
You could consider reading some books on emfs.
Or study websites like https://www.emf-portal.org/en#
EMF-meters usually do not respond to DC ( static fields ), at least if you do not shake them.
You may have looked at a GigaHertz ME meter, which has a "DC" signal output.
It is reasonable good and easy to use, while most meters are pretty unreliable and less solid built.
Usually it is more sensible it is to rely on your own sensitivity.
Lower frequencies operate with both magnetic and electrical fields, measured in nT or mG ( 1 milliGauss = 100 nanoTesla ) and V/m ( Volt/meter ) respectively.
You choose 199,9 nT or V/m if the fields are weaker than that,  otherwise 1999 nT or V/m.
Signals with higher frequencies are not split up in two, are usually called radiofreqencies ( RF or HF ) and measured in all sorts of units, like microWatt/m2, V/m and dBm.
In general you simply hold a meter ungrounded in your hand, should not touch the antenna or keep your fingers away from it in case of an interior antenna.
To prevent damage, you must not over-expose an emf-meter to extremely strong fields ( too close to a sender like a wireless phone, wifi-modem or micro-wave oven ), even when switched off.

Ok, thanks earthworm, start to make a bit sense.
I'm wondering also a bit about dirty electricity... Will be going soon to a place where the wiring is not that good, some socket not grounded. There is a also an induction stove. There are also 2 electrical heaters, with lots of gadgets and sensors etc on them, both very badly placed, one just 10-15 cm from bed, another just next to the main sitting place. It's a very small house, both rooms are tiny. Will not be using the heaters now for sure. But need to plan for colder times later on. Should I try to change their location (not that easy, but probably possible), or would I need to replace them? Or find another way?
Any kind of suggestions/ideas welcome :)

induction stoves are really a disaster, but easy to replace by a gas stove ( plus bottle ).
i would keep an average electrical heater at a distance of at least 3 meters / 10 feet ( preferable more ).
be aware that a modem / router with wifi disabled still produces all sorts of nasty emfs, including dirty electricity.
at night i often switch off all electricity, having a bunch of icepacks in the fridge in order to stabilize the temperature.
near your bed better have no wires at all ( also no telephone- or adsl-cable ), and especially no steel lamps.

ok, thanks. There used to be a gas stove on the place, but of course they renovated without thinking who's gonna live there next.
About gas stoves... Have always had one in my home, love it, also grew up with it, but lately discovered that if you cook a lot with it (or even heat rooms with gas), it can emit real bad gas, that, in the long run are bad for lungs etc... the more I learn, the less options are seen as perfect, there is always a downside.
I have a question about cars... I know that the best are the old ones, with the least gadgets etc.
Problem is, have no driving licence, never had, and planning to maybe get a "voiture sans permis", common in France - one of those cars that you do not need a license for.
There are electric models, but of course... this could be real bad for me if the radiation is much higher. But maybe it isn't? When in my travels loved to use those Honda Dream bikes, 125 CC, but for that you need a licence (not needed in Asia). Felt very comfortable with it. But of course the weather in Europe also would make bike riding not always that confortable with cold and rain etc.
Any hints, anything to think about, about a car without a license? or an electric car? or a car in general ?
Thanks.

Unfortunately, these are the gases that can harm us when using a gas stove, specially if not ventilating well:
nitrogen dioxide (NO2), carbon monoxide (CO), and formaldehyde (HCHO)
Here you can read about it:
https://www.greenmoxie.com/your-natural-gas-stove-may-be-toxic/

thanks for the link.
open windows and doors could be a good idea when cooking on gas then.
it may sound crazy, but i feel like preferring a bit of these toxic emissions above normal electrical stoves.
the induction method is promoted as more safe and efficient, but emf-wise it seems the worst way to go.
well, likely apart from microwave ovens and tribest greenstar juicers.

And if you cannot open windows because of heat or cold, you can install a heat-recovery vent.

(The Canadian- and US-made ones are very expensive, but there is a cheaper supplier in Southern Russia: veteh-group.ru - And sometimes the others show up on ebay.)