In windows you can use a software like Win32DiskImager that create an image file of your SD card and then you can write it on another SD.
Take care that NEW SD must be the same o greather than the original sd, due to the space of the image.
On raspbianos there is present a tool named SD card copier (or similar) that can copy running SD card on another connected via USB.
In this case I do not think the sd size must mach