Whiteboard Sharing for Elementary School Writing Practice

I'm working with my 3rd grade grandchild in another state, using Zoom. We're practicing handwriting skills.
I would like to play interactive games with him in which each of us writes a few words to develop a funny story together.
The shared fun element is designed to have him enjoy the otherwise tedious activity of practicing handwriting.
To this end, I would like to have the elementary school lined writing practice paper on the screen so we can take turns writing on it to develop our funny story.
I thought perhaps a template could be added to a shared whiteboard to achieve this?
Can you describe how I can get this lined paper design onto a screen we can both use?
Thanks,
Gramma