How to scan documents on a LG smartphone or tablet

LG G Pad III 10.1 FHD LG G Pad III 10.1 FHD
LG K3 (2017) LG K3 (2017)
LG K4 (2017) LG K4 (2017)
LG K8 (2017) LG K8 (2017)
LG K10 (2017) LG K10 (2017)
LG K20 plus LG K20 plus
LG Harmony LG Harmony
LG Stylus 3 LG Stylus 3
LG Stylo 3 Plus LG Stylo 3 Plus
LG X power2 LG X power2
LG G6 LG G6
LG X venture LG X venture