The "share sheet" is the small window that pops up whenever you tap the share icon on your iPhone, and in iOS 7, the options listed are limited. No Instagram. No Dropbox. No Pinterest. Besides email, messages, and iCloud, the only third-party options to choose from are Facebook, Flickr, Twitter, YouTube, and Vimeo.
Well, Apple is finally making things better. In the new iOS 8, expect to see more apps included, as well as the ability to reorganize and customize what appears in there and where.
In iOS 8, after finding an interesting article or image you want to share with someone, simply tap the share icon as before. This will bring up your share sheet.
Slide to the right and tap on the new More option. This is where you will edit your Activities. You can reorder them, or toggle off third-party apps like Twitter and Facebook. When you're finished, just tap Done to save your changes.
You can also quickly reorder the options directly from the share sheet by holding down on an icon and moving it, just like you would for app icons on your home screen.
As of right now, there aren't any third-party options listed, as you can probably tell from the screenshot above, but expect to see this thing overflowing with new icons soon.
To see what else you can do in Apple's latest mobile operating system, check out the Coolest Hidden Features of iOS 8, as well as the Best Hidden Safari Features, Top Hidden Features in Messages, and our other iOS 8 tips.