Live shuffling: 3 shuffles, then separate deck into 3 parts (let's name them A-bottom third, B and C-top third), then place them into CBA order and shuffle once more. Some
casinos practice shuffling the deck just by spilling the entire deck on the table and shuffling without any particular order but this happens only every 10-20 hands, after dealer collects spilled cards, he does what I wrote in the first place.
As for online, there is a software that randomizes cards in a seemingly unrecognizable pattern. Several years ago, PS got some award for having the software that deals cards in the most honest possible way for everyone. I remember people saying stuff about it, like it meant that every seat at the table needs to have similar % of winning hands regardless of what the seats play was.
For example, you get 27 and fold pre flop, but if were to call, you would win that particular hand despite what others have. Once again, this is just a theory people presented online