Setting up syncThe first and easier way to make sure all of your or anyone else's photos and videos are backed up, safely and securely, is to turn on sync. With Apple, you can use iCloud Photo Library. With Google, you can use Google Photos. Depending on your needs and circumstances, you may have to pay for extra storage, especially with iCloud Photo Library which only includes 5GB for free (Google offers unlimited free storage for up to 16mp photos and 1080p video), but sync is so simple and powerful it really is a must-have at this point.
Backing up IRL
You'll first need to make digital copies. If it's just a few photos, they're in good condition, and you don't need them to be perfect, you can take pictures of the photos with your phone. Make sure you have great lighting and you're shooting straight, but with a few crops and color corrections, you can go from paper to bits in a few taps flat.
For larger projects, you'll need a scanner or a service that'll speed up and simplify the process for you. Just make sure you sort through all the photos first to remove duplicates, bad shots, and photos you don't really need to have converted first.