Heapifying is the process of converting a binary tree into a heap, which is a special type of binary tree that satisfies the heap property. In a max-heap, for example, each parent node is greater than or equal to its child nodes, while in a min-heap, each parent node is less than or equal to its child nodes. This structure allows for efficient retrieval of the maximum or minimum element. The heapify operation typically involves rearranging the nodes to maintain the heap property. This can be done using a method called "sift-down," where elements are compared and swapped as needed, starting from the last non-leaf node and moving up to the root. This ensures that the entire tree adheres to the heap structure.