There is no definitive answer to this question as it depends on personal preference and skating style. Some people may find that they are more comfortable pushing with their left foot, while others may find it easier to push with their right foot. Ultimately, it is up to the skater to experiment with both feet and see which one works best for them.
If you are just starting out, we recommend trying both feet and seeing which one feels more natural. Once you have determined your preferred foot, stick with that foot when pushing off from the ground. When stopping or slowing down, however, you may need to use your other foot to help keep your balance. Experiment and practice until you get a feel for what works best for you!