Earlier quoted context omitted.
Because no money is being created, it's being reallocated from other people, so it doesn't directly affect the money supply. The recipients are more likely to spend it, which creates some demand (and thus inflation), but it should still be less than the increase in spending power it provides them.
"Because no money is being created, it's being reallocated from other people, so it doesn't directly affect the money supply." And unfortunately that is bunkum. Money isn't stuff. If you take what is currently savings and put it into flow then you will get an increase in production - that is then effectively taken away and given to people who haven't earned it. The result is, over time, an increase in political press…
All you go to do is call the handout a tax credit and give it to almost everyone, and you implemented UBI. In the USA, you wouldn't even need a new system to implement. We have various proto-UBIs written in our tax code, the most notable being the Earned Income Credit, we would just need to "enhance" it.