Depending on where you are located, there may be a local Makerspace group that has equipment you can use. The Milwaukee Makerspace, for instance, has 3 different laser cutters and membership is only $40 a month, which includes access to the wood shop, machine shop, forging, quilting, 3D printing, paint booth, etc.
I don't know what the "most used" software is; literally any program that you can print on paper from will operate a laser cutter. At the MM they used Draftsight, Adobe, Corel, Word...
From there it's just a matter of choosing the proper power levels and speeds for the material you're cutting; there are charts that will get you in the ballpark but it's really something that you just dial-in through experience and experimentation.
Austen is correct. It's all about power first. The very first question you wanna ask yourself is "what do I plan to cut or etch?"
That question will determine the power range you want to go with. Etching on a soft wood can be done with a 40 Watt. Cutting balsa wood or thick paper can be done with a 40-50 Watt. Thicker wood/plastic cutting requires a 60 Watt. Cutting metal......well, let's just say it's really expensive.
And even the power ratings that you may read (eq. chinese machines) can be exaggerated. A 60 Watt is actually a 50 Watt.
And finally, a 60 Watt is approx 1m in length, usually along the back edge of the machine. Lower power have tubes that are shorter. So where will your cutter fit in your shop?
So again ask yourself....what exactly do you want to cut or etch?
Technique? The software isn't a real major factor. It's trail and error on the machine you working on.
**You dont learn laser cutting techniques as a first step**
Learn to design in a sheet environment first. Learn about DXFs and how to generate a reasonable flat pattern. Lasers are incredibly detailed in their own right, to attempt to master that machine without a knowledge of the inputs is setting yourself up for failure.