As is the case with all types of guitar pedals, your looper pedal will need to be powered.
Batteries?
Some looper pedals allow you to use batteries, but to be honest I’m quite hesitant to recommend batteries because they run out quite quickly.
Power Supply!
I would however recommend a dedicated power supply. If you’re dipping your toes into the world of guitar pedals I’d recommend starting with the True Tone One spot 9v power supply. Priced at around £25, it’s a great little power supply which you can also use to power a bunch of other pedals that you might decide to buy further down the line.