1) Paging is used for memory management scheme in OS in which main memory is divided into fixed size blocks known as pages and physical memory is divided into blocks known as frames. Pages size must be equal of frame size.
2) Paging is used for faster access to data. When a program needs a page, it is available in the main memory as the OS copies a certain number of pages from your storage device(physical memory) to main memory.
3) Paging allows the physical address space of the process to be non contiguous. Hence , it deals with external fragmentation.
Please correct me, if I am wrong