Some basic articles - good for new photographers (covers some basic rules of photography, so maybe for the kids)

https://iphonephotographyschool.com/...tography-tips/

http://www.digital-photography-tips....otography.html

https://digital-photography-school.c...-camera-phone/

More relatively basic info but with a few great photos!
https://www.nationalgeographic.com/p...-phone-photos/

https://blog.hubspot.com/marketing/g...res-phone-tips


Now we step up a bit in complexity / quality of tips.

https://iso.500px.com/35-mobile-phot...rtphone-shots/

https://www.pixelz.com/blog/use-smar...roduct-images/