Any information available about a product should be on the product page. Give users as much as you can to help them feel confident about purchasing. Not all users will read it but some need to learn everything they can before they feel comfortable buying, so there's a benefit to it being there.
Examples of such information are descriptions, size guides, shipping details, dimensions, features, performance statistics, FAQs, even how-to videos. If you're selling complex, expensive things like trips there can be huge amounts of information to show like itineraries, room pricing, and package options. If you're selling simple, cheaper things which come with very little information, invest in some custom copy to make yours stand out against the competition.
Of course it shouldn't just be presented to the user in a block of text but should be broken up into relevant sections. You should utilise sub-headings, bullet points, tabs, tables, video, etc to make the details easier to consume.