Every transaction is a file that consists of the sender’s and recipient’s public keys (wallet addresses) and the amount of coins transferred. The transaction also needs to be signed off by the sender with their private key. All of this is just basic cryptography. Eventually, the transaction is broadcasted in the network, but it needs to be confirmed first.
The “requesting a transaction” means you want to transfers some coins (let’s say bitcoin) to someone else. When you make the request the request is broadcasted to all the nodes. Then the nodes verify that (from all the history of transactions) you are not double spending your coins. When verified successfully the transaction is added in a block which is then mined by a miner. When the block is mined, your transaction is confirmed and the coins are transfered.
In 1998, Wei Dai published a description of "b-money", characterized as an anonymous, distributed electronic cash system. Shortly thereafter, Nick Szabo described bit gold. Like bitcoin and other cryptocurrencies that would follow it, bit gold (not to be confused with the later gold-based exchange, BitGold) was described as an electronic currency system which required users to complete a proof of work function with solutions being cryptographically put together and published. A currency system based on a reusable proof of work was later created by Hal Finney who followed the work of Dai and Szabo.
An active investor who has time and knowledge to hunt around for the best possible short-term debt instruments offering the best possible interest rates at their preferred levels of risk may prefer investing on their own in the various available instruments. On the other hand, a less-savvy investor may prefer taking the money market fund route by delegating the money management task to the fund operators.
Government Normally at least 99.5% of the fund’s total assets are invested in cash, U.S. government securities and/or repurchase agreements that are collateralized fully (i.e., collateralized by cash or government securities)—including at least 80% in U.S. government securities and repurchase agreements for those securities. Certain issuers of U.S. government securities (e.g., “Government-Sponsored Enterprises” such as Fannie Mae, Freddie Mac, and the Federal Home Loan Banks) are sponsored or chartered by Congress, but their securities are neither issued by nor guaranteed by the U.S. Treasury.
Over time, money market fund "depositors" felt more and more secure, and not really at risk. Likewise, on the other end, corporations saw the attractive interest rates and incredibly easy ability to constantly roll over short term commercial paper. Using rollovers they then funded longer and longer term obligations via the money markets. This expands credit. It’s also over time clearly long-term borrowing on one end, funded by an on-demand depositor on the other, with some substantial obfuscation as to what is ultimately going on in between.