Is it possible to change the default browser (Safari) of an iPhone?

if you want to alter your preferred web browser follow these steps:

• Scroll down in Settings until you find the browser app or the email app.
• Then tap Default Browser App or Default Mail App, depending on which app you're using.
• To make a web browser or email app the default, choose one. A checkmark appears to confirm it's the default.
• Your device will establish Safari as the default browser app if you delete a web browser app. If you uninstall the Safari app, your smartphone will default to one of your other web browser apps. You'll need to reinstall the Safari app on your smartphone to use it again.

Read more