An assignment consists of something that a student creates, and then uploads into the course for the teacher to grade. For example, the student can write a paragraph or take a photograph. The options in the assignment activity give you many choices in how to run the assignment.
For an assignment, you can require the students to:
Submitting a digital file
Anything that can be uploaded on a computer can be uploaded into an assignment. When the student clicks the Add submission button, the student is prompted to upload a file into the submission.
Submitting online text
In an online text assignment, you will require the student to enter text into an online text editor. This text editor is part of the assignment activity. If students are more comfortable writing the text in a word processor, they can copy and paste it into the text editor.
Submitting work done in the real world
You can use an assignment to require the students to tell you that they have completed an activity outside of Moodle. Even when you don't require students to upload or submit anything, you can still give a grade for the assignment. This is a good way to get work done outside of class, into the grade book.