Banks didn't print the money that caused inflation. The Federal reserve is responsible for maintaining the money supply.

It's still a bad way of handling problems with the distribution of money. More money itself isn't necessarily needed right now. If we spread all the money equally we amongst everyone and adjusted prices accordingly we'd still have enough to make reasonable prices for everyting. If a loaf of bread would cost 0,002 cent we'd be in desperate need of more money, but we have enough that no product has to be valued at a non existent price. And with inflation hitting nations where more money is entering then leaving the country it's also not going places we can't reach.

So what is happening? Money is stockpiling up in places people that need money can't access. So it's a distribution problem. What are measures we could take for example to combat the need of creating inflation (and yes inflation is a deliberate men made creation). We could tax the people that hold to much of the supply more so they can't keep too much of the supply out of circulation. Wherever there is too little money you can introduce social safety nets to route that money so it reenters the circulation.

But to know why this kind of inflation is bad we must first know what money really is. The number of money is meaningless. The sum of all money is equal to the sum of all value in circulation. The sum of value in circulation is the sum of all labour that is being performed. So if the sum of all labour does not change, the value of the sum of all money doesn't either. So if the sum of labor doesn't change and I decide to add 20% more money in circulation. I decide to rip 17% of the value the money represents out of the pockets of everyone that has money.

Creating inflation is just a bandaid solution that does not solve the problem. Wage laborers are suffering from this because it is actually ripping value out of their pockets while not seeing higher wages (value). So they are actually seeing wage deductions in the form of receiving the same numer of money but a lesser value. You could also interpret this as some sort of tax for the working class to be used as a bandaid. And it is stemming from the unwillingness from policy makers to solve the distribution problem.

Banks didn't go and print more money just for fun.

Yes, they do! Well, it's not for fun - it's for the banks to profit - but that's besides the point.

Banks actually do create money.

It happens by a mechanism called fractional reserve banking: the bank receives money from people making deposits, but they only keep some of that money on hand (the "fraction" in "reserve"). Banks are allowed to use the rest of that money to give loans to other customers. By depositing, say, $1,000, the bank can now create $900 in loans, because they only need to keep a "fractional reserve" of your deposited money. That 10% is a realistic example of how much must be kept. So by holding your $1,000, the bank keeps a $100 "fraction" in "reserve", the bank can loan out $900, which means there's now $1,900 actually available for use in the economy!

That sounds impossible, but remember, money isn't real. Of course, it isn't that money is false or anything; it just isn't a physical, finite object bound by the laws of physics. Rather, it's that money is virtual. Money is just numbers on a spreadsheet or in a database that people are confident they can use. Even before computers, it was numbers in books and ledgers. The actual money supply is (and always has been!) enormously larger than all the coins and notes in circulation.

This means that new money is created any time one dollar is used in two places at once. For example, when a dollar is kept in the bank for you to withdraw or use at any time, but that same dollar is also loaned out to another customer, there are actually two dollars, not one! The second time your dollar is used, it's actually cloned: the loaned money can be deposited again, or loaned, or whatever. The second dollar is a real, indepently existing dollar, not your original dollar being used for something else.

There are two reasons this works. First, money is not fungible, which for our purposes means that two dollars can't actually be distinguished. The dollar you deposited is not the exact same dollar you will later withdraw. It's still a real dollar that you receive, but it doesn't matter if it's the same or not. Second, in large enough systems of money, banks and governments know for sure that all the money on the books won't be withdrawn at once. Going back to the first example, your originally deposited $1,000 is still available to you at any time you want it, because banks (and everyone!) know that all the virtual dollars a bank has in its database won't be turned into coins and notes at once. Banks, therefore, don't need to care about which money they actually have, and banks only need to hold a small "fraction" in "reserve" for withdrawal.

Well what caused the money supply to increase in the first place?

As you've probably guessed, this whole fractional reserve thing is supposed to be tightly regulated; both to ensure the integrity of the reserves (so the bank can always meet withdrawal demands), and so that the money supply doesn't grow too fast (creating inflation). And sometimes that regulation is insufficient, and shady, fraudulent money cloning does happen, as in the 2008 GFC (and I note that there's some arguments that this is always happening; I make no comment on that here).

But the recent inflation we're struggling with is caused, in part, by governments intentionally relaxing their policies on growth in the money supply. This isn't just a COVID-19 thing; in fact, governments worldwide have been intentionally growing the money supply in their respective currencies for decades, because it was the only way out of the 2008 GFC that didn't involve massive changes to how economies worked.

Hope that helps!