Jotform offers both Signature and Image Upload fields. You can map either of these field types to a custom Image field in OpenCRM. The image or signature will display on the record(s) created in OpenCRM, and can be merged to PDF or mail merge documents.

This effectively gives you another way of capturing electronic signatures from your customers, engineers, tutors etc. See here for full details of how you can use Jotforms with OpenCRM.