mortgages = get a loan for your house
loans have interest rate, meaning you will end up paying more than you borrowed back over time
fixed rate interest = interest rate is locked in at time of signing the loan. means you know exactly how much you'll end up paying by the end of the loan, and they cant change the interest rate
variable rate interest = interest rate can change, which means if inflation goes bad your rate can go up. may be advertised as the rate can go down, or the starting rate of the loan is low (and possibly fixed for some time) but you can bet your ass they will jack that stuff up the moment they can
do the math upfront and make sure you can afford the mortgage. another thing that's happening a lot these days is low upfront down payments, which make it super easy to "buy a home" but also means more of the home cost will now have interest applied, meaning you'll pay more in the end compared to higher down payment loans. always read the loan terms and give yourself a lot of time to think it over and do research.