Heapsort doubt regarding difference between heapify and build heap

#1

what is the difference between buildheap and heapify function??
can we use heapify to sort ??

#2

hi @riddhiarora156_ae89b0c8b4e40383 buildheap is where u are making your heap and heapify is to maintain the heap quality surely u will use heapify function to sort as bhaiya did in the video