Drawings are a valuable and passionate item for many collectors. You will find beautiful drawings by prominent artists for sale at multiple auction houses. Especially drawings from famous children books have a huge crowd.
There are numerous places where you can find drawing appraisals. Either at the auction houses or with independent appraisers.
Here are some good places to get a drawing appraisal
And an example of a video with a drawing and an appraisal
https://www.pbs.org/video/appraisal-frank-lloyd-wright-drawing-7xlbk0/