In a Comment on a prior someone remarked that one should form a LLC before you start as a free-lancer. As for if you should form a LLC I can’t give you advice on that, it depends on what state or province and country you live and work in.
I will say you need three professional people in your life, a Lawyer, an Accountant, and an insurance agent.
In terms of a lawyer you will need contracts written up, as well advice on legal structures (LLC vs S-Corp vs what they call it in your country). You should find someone who is used to working with free-lancers and understands your business model. You probably don’t need the big white shoe firms that service big companies (at least not yet).
You will also need an accountant. Tax compliance can be complex, even more so if you work across borders.
In terms of insurance it will depend on three things what you do, who you do it for and where you do it.
In every case your best bet is to talk to other free-lancers in your area who they work with.
NOTE: I am not a lawyer, accountant or insurance agent, this is not professional advice and I have no clue.