Missing icon

Safari can't actually be deleted from the iPhone. If its not in a Home Screen, swipe to your last home Screen, then swipe one more time to access App Library. You can use the search bar there to find Safari and drag it onto the dock.

Link-> Find your apps in App Library on iPhone - Apple Support

The bottom dock is a customizable area. No icons can be missing or have to be part of it. It just depend on what you want to have there.

By default Apple places the Phone, Mail, Safari and Music apps there. But you can have whatever you want.

Why do you think apps are missing from there? What do you have there now?

Find it, and just drag it onto the dock. If you already have four other icons on the dock, you will need to drag one off before you can drag Safari onto it.

Glad I could help.