So -- if you are asking "How do I start a business online" -- here is some very straight dope for you.
If you have no clue how to run a business - then you need to get a little knowledge. If someone tells you that you don't need any knowledge, don't hand them money, they may be counting on ignorance to rip you off. Find a business textbook and read it or take a beginning class. Just because it's cheaper to start online does not mean that you can just ignore all the formalities. You can work for someone else online to help get your knowledge but DO NOT START your own business, build a website, or start posting content until you have some facts.
1. Online business is not a playground. There are legalities here just like anywhere else. Just because you hear of others getting away with crap they shouldn't be doing is no damned excuse when YOU get caught. "I didn't know" doesn't fly when your server pulls your site offline or in a courtroom. You are not a little kid, you are an adult and hold 100% responsibility for your actions. If you get caught doing something against someone else's TOS, they will ban your butt - If you get caught doing something illegal you can lose your website, get fined, or go to jail depending on the offense. You can not get over by blaming someone else. Recognize that responsibility. Nobody owes you Sh** from Shinola - so get over yourself and act with integrity.
2. Get to the official trademark and copyright websites and read up on what constitutes trademark and copyright infringement. You don't want to start your business reputation by being slime mold who steals.
Here's links (Sorry they are US, but will give anyone a good idea of their own country's laws, too - they are pretty much the same globally).
Patents: Start Here for First-Time Filers
Copyright: U.S. Copyright Office - Frequently Asked Questions
3. Find out what you need to be legally in business. Can you fly as a Cottage industry or do you need to incorporate? How much is the cost? Etc.
4. What types of documents are legally required on a website? Know that, know what disclaimers are and which you need to protect yourself. Find where to get legal copies or have them written for you by a professional.
5. Are you thinking of shipping items? Do you know the laws about shipping - domestic and internationally or do you have a company that will ship for you?
Find out what shipping laws are in the product planning stage before you need shipping, not when it's time to ship things.
6. Are you thinking of advertising a product - yours or someone else's? Do you know what constitutes False advertising? Do you know and understand FTC requirements for advertising? You better.
7. Are you thinking about a Joint Venture with someone? Are they suggesting a plan that will hold you leaving the bag if they decide to take the money and run? Have you asked for a contract? Have them send you a contract and have a lawyer or at least a paralegal look at it before you sign it. Do not get caught in a position to be held responsible for anything your partner might do that is fraudulent - including stealing form you and disappearing.
8. If you don't even know what you want to do yet - you aren't prepared to start yet. Period. At least know where you want to go with a business. Don't think you can come into a forum and realistically get an answer to a vague question such as "how do I make money online" or "what niche should I be in". No one business plan works for everyone and if you don't even have an idea of what you want to do, nobody is going to be able to help you - but........there are a lot of people who have products they'd love to lead you to buying. Being realistic about your preparedness to start a business can save you a LOT of money and frustration.
Now THAT'S how you start in online business. Once you have figured out that these steps are part of ANY business, offline or online, and are ready to actually be serious in the business market, feel free to ask questions when you need help. By the time you get done with those 8 steps you will probably be able to ask questions pointed enough that people can realistically answer them. You will also avoid being seen as scammer bait.
And THAT is the truth about starting a business online.