system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5: When countries provide foreign aid (cash) to others, how do they transfer the money?

Do counties cut a big cheque, e-transfer or maybe a cash delivery?
gpt
Most of the world's banking industry is centered in the US at the Federal Reserve.  Every country and just about every major bank has an account with the Fed that contains a significant portion of its assets.  When one country wants to give foreign aid to another its usually just a matter of deducting funds from one country's national account and putting them in another country's.

So for example, if Canada gives Botswana $100 what will most likely happen is Canada will tell the Fed about the transaction and the Fed will transfer that money from the Bank of Canada's Fed account and stick it in the Bank of Botswana's account.  

If Botswana then buys $100 of grain from an Italian company they'll let the Fed know and the Fed will then take that money out of the Bank of Botswana's account and move it to the bank that the Italian company uses.

Its likely that no money will actually physically move as a result of this process - its just the Fed changing account balances, similar to if you wrote a check to someone who used the same local bank as you.

There are instances in which countries will try to bypass the Fed's banking system - for example when India buys oil from Iran.  But the countries in these cases typically try to avoid paying in cash, instead they'll do the deal in something like gold or as a barter deal in which they trade one product directly for another.

In the case of India buying Iranian oil they'll just stick the gold on a plane or boat and send it directly to Iran.

You also tend to see similar deals with Russia.  For example, Russia has historically provided a large amount of "foreign aid" to Venezuela.  But that aid isn't in the form of cash, its typically in the form of oil field equipment that they ship to Venezuela and technical services provided by oil engineers that they send to run the equipment.

Likewise, Venezuela has provided a huge amount of "aid" to Caribbean countries.  But the aid isn't in cash, rather its in oil that Venezuela ships directly to them.