Since the introduction of iOS 11 the experience of drag & drop has dramatically improved on iPad, as you are now able to drag almost every file type to other applications, for example images to the Notes app.
But there are a few situations where you don’t want to switch between applications and that is where Yoink comes in. With Yoink you can simply drag any file type like texts, images, links, mails and much more, to the application where these dropped items will be stored, it is like a shelf. Furthermore, Yoink supports all views, like the side-by-side or split-view which is super handy.
A good example is that you are going to copy a few images from the Photos application to Yoink. You select all the images you like and drag them over to Yoink. As you drop the images Yoink automatically creates a collection and if you move this collection to Notes all of the items included in this collection will be dropped to Notes. (See the GIF below)
Additionally, all items inside of Yoink are indexed by the Spotlight which makes searching for items very easy. And you can even drag & drop the search results!
Yoink also includes a share sheet extension for sending items to Yoink without even opening it. Furthermore, the app offers a keyboard extension, where you can drag already stored items and drop them in almost any other application.
There are many alternatives to Yoink which offer almost the same functionality, though I stick with Yoink because there are great new features planned like url schemes, download files from a url to Yoink and it will support the Files app soon.
EDIT 5th of December: added official video