how i can download free apps in appstore?

In most cases you must provide a method of payment before you can download any app, even if it’s free.

Download apps and games on your iPhone or iPad - Apple Support

Download apps from the App Store on your Mac - Apple Support

Have you ever downloaded from any App Store before it’s the same way just pick selected apps or app tap get and it will download but before loading scroll down and read what info is required and if it’s apple approved most i won’t get unless apple approved. There is an app that i would like to download but the terms and conditions and requirements won’t show unless you agree to conditions and terms by that time your whole phone would have been ransacked. On picking be smart.