We've made it easy to send materials like homework, exercises, etc. to your teacher anytime. Just head to the Classroom - Messages page to send a message to your teacher, and use the file upload option to upload a file.
What if you've got homework from a book? Just take a quick picture, and send that! Or you can just describe the homework to your teacher, and they'll be able to help. They've probably helped with the exact same topic literally thousands of times.