Student's responses can be downloaded as PDF files. Then they can be printed or submitted to your Learning Management System (LMS) for grading.
To save their responses as a PDF file, students use their browser's Print function. Each browser handles this slightly differently. Here's how it looks in Chrome:
Select Save as PDF, and then click Save
Once they've downloaded their responses, students can submit them for grading via email or upload them to an LMS so the instructor can use the LMS grading tools.
For more assistance converting to PDF on an iPad assistance, check out Save and mark up PDFs.