How to convert any native app to ionic cordova plugin

Hi,
my question is
How i can include any native functionality like


in my ionic v4 app?
how to convert any native app to ionic cordova plugin

How is this thing different from any of the myriad existing barcode scanners?

It’s not about barcode scanners,
I do need to know how i can convert any Android app to ionic cordova plugin.

so that i can use that native functionality as i want to have that in my ionic app.