Depends on the OS & hardware architecture. Usually each page share a fixed size of 4kb(check with getconf PAGESIZE)
The 4kb memory page is one contiguous space in the Main Memory
Memory Page Size
We need to find a fine balance overhead and flexibility when deciding the size of the Memory Page
With more overhead, it comes with more flexibility, vice versa
When we want more flexibility, we should reduce the memory page size, so we can more freely to manipulate the Main Memory with Virtual Memory. But that means we more space for Page Table to manage mapping