What does i,v in pairs do actually do?

I have watched tutorials but they dont make sense to me

Iterator loops
Generic for loops

Call them what you want, but it's always going to be called a foreach loop to me. pairs is a generator function which takes a single table and returns next and that table you gave it. next is an iterator which can go through all of the elements in a table. I won't go into how it does it because you don't need to know because you can't even spell 'sense'.

For every time the loop runs, i,v (k,v) is set to the key and value pair for an entry in the table. This happens for every element in the table.
ipairs does a similar thing but it only goes over the array part of the table.