How can i make the project ticket number appear on a form?

[OAure]

in a project we set it up so that some issues require forms, others do not. The forms are sometimes exported to pdf and sent to customers. if they bring the form back to us with questions i'd like to be able to quickly reference the encapsulating ticket associated with the form. So i'd like to add the ticket number to the form if possible. Currently we are creating  a separate number for each form, but i'd love to automate the process to reduce error. anyone have any ideas for a budding amateur?