This morning Apple ran through with its WWDC announcement, however, they left something out that was only included on the Preview website for the update. You will now be able to set the default application for Mail and Web Browser
Apple has been heavily criticised in the past for forcing all iOS and iPadOS users to use its built-in Safari and Mail applications, with no option to change the defaults.
Set default email and browser apps.iOS 14 Preview website
With iOS 14, you can set a third‑party app as the default email or browser app systemwide.
Some examples of optional iOS Web Browser would be Brave, FireFox, Opera Mini, and Chrome.
Of course, some examples of optional iOS Mail applications are Spark, Outlook, Gmail, and our newly found love HEY Email.