How prevalent is magic?

I know YGWV and all that, but how prevalent is magic in Glorantha? I'm reading Thunder Rebels at the moment and hoping to run a campaign in Glorantha in the near future based in Sartar. I'm probably not going to use HQ rules. I've heard that Glorantha is a higher magic setting than like Harn. I've heard that Heortlings can fly on the battle field and shoot lighting bolts. I'm assuming that everyone cannot do such magical feats.

What can a common Carl do, if anything with magic?

And if they can do some magic, is it obvious that the feat was done by magic?

Where does this magic energy come from? I'm assuming the gods. But does some come from their ancestors? Would each have some magical reserve?

Thanks