Apple's Shortcuts app offers hundreds of pre-written algorithms designed to accomplish tasks that would normally take many steps in just one or a few steps. For example, the Home ETA shortcut uses Maps and Messages to find your location, find a route home, estimate the time that route takes and text that time to whoever you set up the shortcut to send it to, all with a single tap.
Note: if you're wondering how to customize or change your app icons using custom images or your own photos, click here to learn how.
If you want to share your shortcut with others (or any of the pre-made shortcuts), simply open the Shortcuts app and tap on the three dot button in the top right corner of any shortcut in your Library.
If you have ever received a zipped or compressed archive as an email attachment and tried to open it on your iPhone, you've seen that you can view the contents but can't edit the individual files, or share them individually. Surprisingly, as of iOS 12, there is no built in option to extract zipped files. You can, however, easily create a shortcut that will do it for you. Here's how to do it on iPhone and iPad:
The new Shortcuts app, which is a reboot of the old Workflow app that launched with iOS 12, lets you create simple programs that use a variety of apps to accomplish a task. For example, the Time Machine shortcut for Photos lets you quickly pull up all of your photos from one year ago. This is just one of hundreds of pre-programmed Shortcuts found in the app's Gallery. To use a shortcut you need to first add it to your Library from the Gallery.