Rahulsingh What you want to do is in powerbi desktop create two parameters that contains server and database name for your databases (i am guessing you have sql server database). Then create all your reports from first database in powerbi desktop and save that as powerbi template file (.pbit). Next when you open that template file it will ask you for values for those parameters and you can enter in that for all other databases. By this you won't have to create seperate pbix for each database and you can use just one template file for all your databases.

Hope it make sense.