It's not an ideal situation, but that's partly on us. Back in 2008/09 or so there was talk of making money more accessible, and the National Federation of the Blind came out against it because they thought it implied we couldn't handle money as is. Honestly I don't associate with either the NFB or ACB, but that goes back to my aversion to politics.[^1]

Coins are already tactilely distinct, bills are the problem. Assuming we know the denomination, we usually fold them in different ways to differentiate them. Singles may be left unfolded, fives folded hamburger stile, tens hotdog style, etc. There's no set way to do it, it's up to the individual. There are bill readers, both standalone and as phone apps. TheiPhone may have one built in as part of VoiceOver or the magnifier app, but I'm too lazy to check right now.

I personally avoid using cash where possible as I don't like keeping track of change.

[^1]: Standard disclaimer: I only speak for myself. Blindness does not respect class or creed or culture, so every blind person approaches their situation from a unique worldview, and there's debate among the blind whether a blind "community" can be said to exist. I personally say no for the reason stated above, but again, I only speak for myself.