By using something called a listing template. Created using html
There are third party suppliers who can create them for you some are on the eBay business partner page there are companies like Frooition who provide this service. I think it starts at around £250
Alternatively you can sketch up what you want and use a service like fiverr. I did this for £30. I store my templates and list via a third party provider, Selro, who do my inventory management, shipping, reordering and multichannel support.
Some third party providers supply free templates - I started that way using a service called Inkfrog. From memory it was about $20/ month for 1000 listings with free templates.