Hello @ crypto.piotr, attending to your question:
"HOW TO LAUNCH STO (security token offering) AND WHICH PLATFORM TO CHOOSE?"
First, a simple way to launch STO can be through the Tronscan platform
You can create a wallet on this platform and once inside, you go to the TOKEN menu, a submenu will be displayed where you will find the TOKEN RECORD entry, there you can create your token at a price of 1024 TRX, right now it is at $ 0.015660 that is, in total, to create your token will cost you approximately $ 16,03584, and taking into account the market.
I hope this information is of your use, receive an affectionate greeting