A UPI ID or a Virtual Payment Address is what you share with people with whom you want to make transactions with. To create your own UPI ID, you must download the app of your choice and register. While registering, there will be a section that asks you to enter your UPI ID. You cannot send money to someone or receive money from someone if you do not use your UPI ID. This is the only detail that you use instead of sharing your bank account number. 

UPI is a secure way to conduct transactions, without worrying about someone misusing your bank details. There are daily transaction limits, where you won’t be able to send money over Rs. 1 lakh per day. There have been reported cases where UPI accounts have been hacked, so it’s better to take precautions to make sure your account is safe. When you are making transactions to second parties, make sure the dealer is safe and authentic.