One of the best features of Continuity across Apple devices is Handoff. Handoff allows Apple's first-party apps and any third-party developers to send an app's data seamlessly between devices so you can "pick up where you left off."
So, for instance, you can copy text or an image on your iPhone and paste it on your Mac.
Likewise, you can start composing an email on your iPad and finish writing it on your iPhone.
Handoff works with Calendar, Contacts, Mail, Maps, Messages, Notes, Reminders, Safari, Pages, Numbers, Keynote, and any enabled third party apps.
Some examples of third-party apps are Spark, Chrome and Pocket.