How can i zoom in my android apk, where i have html code?

i have apk, which have two sides.

Backoffice when you can edit content of the app.

And apk when is displayed the content.

The problem...

1. I need allow to zoom in HTML pages in this app for Android and too from iOS

2. I found this parameter:

meta name="viewport" content="width=device-width,initial-scale=1,minimum-scale=1,maximum-scale=2,user-scalable=yes,minimal-ui"

This parameter allow zooming only on iOS, but on the android app this not working, do you have some another solution, how can i enable zooming for booth systems?

Thank you.