Is there a way to make the header image display on all pages?
I hope you are well today and thank you for your question.
Currently in the shapely theme the Header Image is not displayed anywhere as reported here https://github.com/puikinsh/shapely/issues/21 so you have to develop custom code to display the header image on all pages.
Developing custom code for custom functionality is beyond the scope of support that we provide here.
If you are not a developer then you can consider hiring a developer to develop it for you. You can hire a developer from any freelance site. Colorlib recommends the developer https://www.upwork.com/freelancers/~011652ffec8865c6d5 http://freewptp.com/contact