Thanks for reaching out.
We do have multiple free themes that you can take a look through on the Shopify theme store. Could you let us know what you would like to do with your product description? This context help us assist you a bit further when it comes to making customization changes to your theme.
We do have third-party applications on our Shopify App store that can offer some additional features. I went ahead and added a few that assist you with customizing the product page, feel free to take a look:
Let me know what you think.