Unfortunately, Apple has not created a system setting for choosing your own default browser. Depending on the app from which you want to open links, the app may allow you to choose the program to open the link in. Also, I read this in another thread but haven't tried it myself: <blockquote>You can send pages from Safari to Firefox by tapping the share icon (the box with an arrow coming out of it) and choosing Firefox as the destination. If Firefox is not listed in the options, tap the More button (three dots) and tap the switch next to Firefox to enable it.</blockquote>