how to delete applications on iPhone 6s

I sincerely hope the articles below assists you:

https://support.apple.com/en-us/HT207618

https://support.apple.com/guide/iphone/remove-apps-iph248b543ca/ios

If you're wanting to delete an app, find the app on your homescreen, press and hold it until it starts to "wiggle" and then press the "X" to delete/uninstall it from your device