I cannot update my MacBook AIR its still on OS YOSEMITE
I have a 2014 MacBook AIR, I recently formatted and when I rebooked it was updated with the Original OS YOSMITE , this MacBook can be updated to BIG SUR but I don't how .
I tried the usual way to update , but it says NO UPDATE AVAILABLE.
kindly help me , I cant download any applications ( it says update software to download )
TIA