The most common way to do this is to have the Photos app on MacOS set to "download originals," then use whatever backup solution you like best. I highly recommend setting this up. Last month through some sort of iCloud glitch my fiancé lost almost all of her photos from before the beginning of this year. We've escalated it to their highest tiers of support but the photos are gone. Redundancy is important, and even the best providers aren't foolproof. It was devastating to lose all of those memories.