Magento PDF Invoice Customization

[login to view URL] this is an e-commerce marketplace website, based on Magento 2.1, we are using vnecoms multi-vendor marketplace software, we have two control panels, one is Magento Admin Panel and second one is vendor panel. Vendor Logo and Name on Invoice First we want to add vendor logo and vendor name on invoice print as per screenshot Return Policy Page Second we want to add our return policy as a second page with invoice print But order number and customer name on return policy page should be dynamic, according to particular order, please check attached image example Important note: vnecoms Multi-vendor marketplace software provides vendor panel, where vendor can also print invoice, so all changes must be reflect on both control panels