How to scan documents on a smartphone OnePlus

OnePlus 6T OnePlus 6T
OnePlus 6 OnePlus 6
OnePlus 5T OnePlus 5T
OnePlus One OnePlus One
OnePlus 2 OnePlus 2
OnePlus X OnePlus X
OnePlus 3 OnePlus 3
OnePlus 3T OnePlus 3T
OnePlus 5 OnePlus 5