Liveworksheets transforms your traditional printable worksheets (doc, pdf, png...) into interactive online exercises with self correction.
In order to make your worksheets interactive you have to upload the document, which will be displayed as an image, draw text boxes on the gaps and enter the right answers in the boxes.
There are other options to make different kinds of exercises (join with arrows, drag and drop, etc.)
You can save your interactive worksheets as public (if you are the author of the original document) or private (if you are not the author). In both cases you'll be able to send the exercise to your students.
You can find the full tutorial here, and the video tutorial here.
You can start making interactive worksheets here.