Any way that you will remember. Personally, I just put 1s, 5s, 10s, and 20s in different parts of my wallet.

There is no standard technique. My wife's technique is to fold based on frequency of the bills. The more folds or complicated folds the rarer and generally more valuable the bill.

$1 not folded (seriously, why is this not a coin?)

$2 corner folded since they are so rare.

$5 folded in the middle lengthwise (nearly square)

$10 folded twice in the middle lengthwise

$20 folded in the middle heightwise (long and narrow) This can be annoying because it is bulky for more than $100

$50 folded twice in the middle heightwise then lengthwise (short and narrow)

$100 not folded and in separate section or corner folded like a $2

We rarely need to carry lots of cash any more, it used to be necessary sometimes in the days before online credit card verification.

bigger bills (do they even still have those?) Not folded. Wrapped in paper or envelope per denomination and she just remembers how many of each she had. She will sometimes to this with $100s now.

Have you considered using those shaped paper clips? The come on heart,star, swirl, etc and you can just clip certain bills together. This is a pretty easy way to keep them separate but not have to fold every bill as soon as you get it

I carry a front pocket wallet that is half size to Starr. I fold $1 in half, $5 into quarters with the red five out, and $20s into a square with the big 20 facing out.

I’m married with a kid so I don’t know what those other denominations are.

I use a money brailler, just slide your bill in and squeeze, it handles $1 bills through $20 bills.

I never did that. Now, I use seeing AI to count money. I flip each bill over after reading to read again just to be sure. It's not steered me wrong yet. I don't carry a lot of cash unless I know I'm going places where cards are not really used, like up in the mountains where my family is from, and even they are getting on board with it so...