Did you think that fossils were all bones and nothing more? Nope! Some fossils are impressions left of footprints or tracks. Other fossils are impressions left by skin textures. Sometimes even the tissues of an animal can be preserved, or visible in the fossil. It can be hard to figure out what we're looking at in a fossil of a soft-bodied invertebrate from long ago, but dinosaur fossils are usually easier to recognise. Some later dinosaurs may have had skin rather like an elephant, while others had skin and feathers like modern birds. There are many fossils with skin impressions showing scales much like a modern iguana or alligator!
Here are some articles about a dinosaur fossil, a nodosaur, that was preserved with skin or skin impressions and some of its innards:
Check out this link at https://earthlymission.com/dinosaur-mummy-science-discovery-nodosaur-intact-canada/ - for fascinating photos of a nodosaur fossil found in Canada!
If you like to imagine what it's like to work in the field gathering fossils, try this link https://www.huffpost.com/entry/dinosaur-mummy-unveiled_n_59187ca4e4b0fe039b35436f - for a video of the attempt to lift the wrapped fossil onto a truck.
For more than this brief note, look to this link for better explanations. https://earthlymission.com/perfectly-preserved-dinosaur-mummy-last-meal-science-study-nodosaur/ - for a discussion of this nodosaur's last meal, and wonderful drawings of the dinosaur as it would have looked alive.