@Dhanusha , your ask is not about case archival, but simple backup. There’s no such functionality.
Why do you want to backup into another database/table? It won’t lower your costs; and moving your older data into another database means you’d have performance problems accessing on the other database.
Case archival allows you to search, retrieve, and review inactive/older cases and all of their hierarchies and associated data. It does by lowering costs. Please go through documentation that @MarijeSchillern has shared.