How do you encode your videos?

So I use my drone just for home movies and recreational stuff, I'm not a pro or anything. I had the Spark and I would just store the raw 1080p30 videos it produced, which was fine. Now that I've upgraded to the M2 I can record 4k videos, but the raw files are too big for storage long-term I think. What would be the best way to encode them to into smaller sizes without losing too much quality? What do people here do?