1. In order to solve your issue I have captured a video for you on your site. please watch and follow the steps shown in this video: https://streamable.com/jwcj6e you have to add the product shipping information by editing the product in order to show the additional information tab on the single product page.
2. I have checked your site now and found no issues. I have edited the product and all the product information showing perfectly fine on the front end of the site. I have captured a video for you on your site please watch it and complete this video for a better reference: https://www.veed.io/view/ce43cf21-28ce-45ce-a2cf-b351c0833e48?sharingWidget=true
Regards 8Themes Team.
One standard license is valid only for 1 project. Running multiple projects on a single license is a copyright violation.