Printing Copies

If I have a shape, lets say a small sphere, and I want to print 100 of the same small shape.
What is the best technique? is there a particular command I can give the printer to
print the same/ as in the copies? or do I need to make my file like that?

The quickest way to go would be to load your file into slicer, and then click “more” (little green plus button in the newest version of slic3r) until you have the number you want. Then export the .gcode and load it into your host software and print!

I would suggest loading it to an SD card and printing from that if your printer has the tetherless printing. I print multiples of small trays often, about 16-25 per print. The way rufu5 suggested is how I do it. If I print over usb, my extruder head stalls multiple times during a print. If I print from the SD card I have no issue.

Is USB power saving turned on for your computer?