When was the last time you went to the bank teller and handed them $100 in cash? I haven't done that in well over 20 years now. Notes and coins represent less than 3% of the money supply in countries like the UK and US. It's not what money is any more.
What does that mean? You think someone is physically wheelbarrowing something around between banks when you make a transfer? The banks settle up at the end of day and the net amount moved between banks is far smaller than the total transferred. What do they settle up in? Another layer of electronic funds you don't have access to.
If even the smart people on HN can't understand this it's little wonder the finance industry has such a stranglehold on society. The banks just run a ledger. That's all they are doing. But it's a ledger they control and they are allowed to create new money in it. In fact 97% of money is created by the banks when they issue loans.
It's a fundamentally different model to the antiquated "banks lend out your deposits" one.
You don't understand what it means for a bank to receive $100 in its bank account? This has nothing to do with lending, except that deposits are loans from you to your bank.