Introducing canvas api using laravel and js

I want to introduce canvas api so that I can sign the contract.

I want to save what I wrote with canvas api to DB.
Please make it responsive.

Summarized in XD.
https://xd.adobe.com/view/abdb3038-059b-41f4-934d-113e4113b184-fe88/

The canvas api under development is in the attached file.

You can write on your PC.
Responsive is not supported yet.

thank you