When you come across a link in an app on your iPhone or iPad, sometimes the link opens a page in an app's own built-in browser and other times it opens a Safari-based page in the app via iOS's Safari View Controller. The latter is a better experience because it remembers any accounts you are logged into in Safari and lets you use any ad-blockers you might employ. It also provides a reader view.
With the Browsecurely app, you can open Safari-based pages in apps such as Twitter that don't use the Safari View Controller to take advantage of the above benefits. Browsecurely also prevents apps from tracking you and your browsing habits.
After installing Browsecurely, you will need to add it as an action extension. To do so, open a page in Safari or another app that has a share button. Tap the share button and from the share sheet swipe left on the bottom row until you get the More button at the end. Tap More than then tap the toggle switch for Browse Securely (which mysteriously splits the app's name into two words).
With Browsecurely added as an action extension to the iOS share sheet, you can now open a link in, say, the Twitter app as a built-in Safari page. The drag is that you will first need to open a link in Twitter's built-in browser before you can access the share sheet to open it as a Safari page. Leaping through this hoop is worth it, however, if you are going to a site that you are already logged into in Safari, for example, or want to block ads or enjoy Safari's reader view.
Browsecurely is free and although the app advertises in-app purchases, they are merely suggested donations for the developer.