This is another content page that you can easily control from the back-end of your website. You can match the exact Shipping & Returns policy of Supplier or you can make yours a bit more restrictive if you prefer so as to avoid issues with any return delays or to reduce the reasons when a return would be allowed.
No technical programming is needed. You simply filling a simple form on the admin of your website with the text and format you want, just like using a Word document, and the change will display live.
Note: Even though this is a Shipping & Returns Policy page, you can still work in a few lines with good keywords for your SEO by mentioning a little more about your product types or brands.