Hello @catherine_alexa ,
Thank you for contacting the Instructure Community to discuss your question regarding converting PDF assignments to Word, so students can annotate an assignment. If you would like to create an assignment, that requires students to annotate a document, you can upload a Word or PDF document and students may annotate either file type. You may upload the following file types for students to annotate: What types of files can be previewed in Canvas? - Instructure Community .
Or, would you like students to peer review each others' work and make annotations on their peers' submissions? If so, the student can submit either a Word or PDF document and peer assigned students will be able to annotate either file type. Note, If the peer reviews are anonymous, the students will not be able to annotate the document. Further, when creating an assignment, you may restrict file types to Word, only. For more information, please review : How do I submit a peer review to an assignment? - Instructure Community and How do I create an online assignment? - Instructure Community .
Lastly, Canvas does not offer a converter for PDF to Word. But, you may find one online from a different vendor.
I hope this helps ! Again, thank you for reaching out to the Instructure Community.