Ok, so what country do you live in? I know we can do that to here in my country but we need tp register for a VAT number as VAT is a must mostly here.
The US. I don't want to say what state I live in but some cities and states don't get on your case about filing all the paperwork.
It's not necessary if you're just starting out or if you have a small at home business.
Yeah, from some time (it wasn't always available) you can do that in Poland too. Yes, you have to keep a registry of your transactions and pay tax. You can do this below certain income treshold, once you go above you need to register... And if you're even basic fulltime freelancer you'll go above that amount quickly

. Like, the amount is so small it's for side hustles only, not main income source

. But it's really cool, we didn't always have that.
Yeah, I skipped register a company, that said, I always invoice from a company though not mine. Better keep that taxman away and pay your taxes after deductions ofcourse.
Yeah, some people do that. There are 'business incubators' that'll let you invoice under them or we also have our own Fiverr competition

that let's you issue an invoice through them and you get contract for specified work from them and sort of work under them. Never used that but sounds handy.
In Israel you must open a business if you want to get paid as a non-employee, so yeah..
Yeppp even most IT specialists that work in the office, offline, for one employer they're mostly sole proprietors. And especially someone working with multiple clients and remotely, clients will want invoices, etc.
Me? I was registered and not registered multiple times, even had a foundation at one point (now THAT was a legal hassle, not recommended). Probably if you're starting out and have only minimal earnings it's too early to register. Or if your earnings drop then you can pause what you already registered. But once you do get to that point I'd check and think for a long time because some forms of registration will give you tax benefits and some will drown you in crazy high taxes so watch out.