You don't need to install any fonts on iOS 9.
I modified Ionic's $font-family-sans-serif SASS variable, which does now the following:
* San Francisco on iOS 9
* Helvetica Neue on iOS < 9
* Roboto on Android
* Segoe UI on Windows Phone
$font-family-sans-serif: -apple-system-font, "Helvetica Neue", HelveticaNeue, "Roboto", "Segoe UI", sans-serif !default;If you don't use SASS:
body {
font-family: -apple-system-font, "Helvetica Neue", HelveticaNeue, "Roboto", "Segoe UI", sans-serif;
{