That's something that most programs don't even try to explain, and something ive wondered about - how does the money affect competition, both for goods/services and labor?
If you're affecting very small percentages of the population, the impacts seem minor. We've seen this with analysis on raising minimum wage to about $10/hr. Most people make over that amount (or work in excluded roles), so the impact is small. Raise it too much too quickly, and some industries experience issues due to costs passed on in their products/services, and inflation can become detrimental to the people at the bottom.
I wonder how this sort of thing will work out with something on a nearly universal scale - Social Security. To keep up with inflation, we need higher payouts. To keep the program solved, we need more revenue. This can be achieved with more workers, but relies on ever expanding population to cover the prior generation. Or it can be achieved with higher earning workers, which generally requires higher prices which potentially drives inflation, or though higher consumption (not very competitive on the global market due to cost of living, so not likely). Or we can raise the payroll taxes to cover the payouts.
Anything besides the higher output/consumption is likely to result in higher costs to consumers and drive inflation. More money being in more people's pockets also means more competition for constrained resources, also driving inflation.