Update field with value from another field

Update field with value from another field

Hey, community, 

I have one request; I can not figure out how I can do it via workflows. If you can help me, it would be great.

I have a custom field (checkbox) in a Deals module. I need to put the value of this field (Y/N) to all invoices ("Invoice" module) that will be created within this particular Deal. 

Thank you in advance