Basically, Ramblingrose22, it is 'printed' by the BoE (though it's just done by keying in amounts on a computer, not by actually printing cash). Some of the money is 'borrowed, in that it is sold as government bonds, which are for a fixed period at a guaranteed rate of interest. People purchase bonds as a safe way to save, they get the interest and are guaranteed to get the principal back at full term. Lots of our private pension moneys and private investments are held as government bonds (aka gilts). So this is useful for savers and investors. Money has been 'raised' by these means for hundreds of years.
The rest is owed to no-one. The BoE pays the governments bills when told to but as the BoE is 'owned' by the government (us) it doesn't have to be paid back. .
What we don't do is 'borrow' from other countries or from billionaires.
Now, most economists absolutely know this. So all that stuff about 'maxing out the credit card', or 'running out of money' is nonsense. We (i.e the government) can issue as much as it wants so long as it doesn't lead to inflation.
We can do this because our currency isn't backed by gold and silver reserves, it hasn't been since the early 1970s. (And neither is any other country's money.)
The idea that a national economy is like a household economy, that it has a finite amount of money, is absolutely false. If you were to google 'government budgets are like household budgets ' you'll get pages of results of economists saying that it is not so. It's a bit mind boggling, because that's what we've always been told and it's hard to let go of it.
And taxation doesn't fund spending, taxation ensures that there isn't surplus money in the economy (which would cause inflation) and is a way of redistributing the nation's 'wealth.
So the money that the government is at present putting into the economy is helping the economy to survive, keeping thousands and thousands of businesses afloat, and by paying wages also doing the same as we spend it. All that raising taxes will do, if it's done before the economy recovers, is to limit the money that can be spent into the economy and slow down our recovery. Those years of austerity post 2010 were completely unnecessary and actually hampered recovery from the global financial crash on 2008.
But using the 'household economy' myth has been useful to tory governments because they don't believe in state spending. They want a minimal 'state' with lots of privatised 'public' services. It's ideology driven, not practical.
This is a good site to look at if you're interested and want to find out more:
gimms.org.uk/2019/02/10/uk-government-spending-taxation-bank-lending/
But there's loads on the web! Look for MMT