Google isn’t in the business of making a PDF editor but there are a few by 3rd party vendors that work on Chromebooks and with Chrome Browser.
It would be better if Chrome was able to recognize the PDF files that it was written to. On the other hand, I don't like getting rid of the possibility that I'll get all my PDFs in my Chromebook back to my Windows or macOS. What about the idea that Google will someday make an official Reader PDF and Markdown reader? That's what the folks from A2C do. You can go to a site like A2C.com and buy their Kindle reader software, install it, and then read PDFs off that. But, like I said, I have no idea if that's going to come any time soon or in the near future. The other option is to write PDF files into Windows, macOS, or Linux files, convert them to the type of format Android recognizes, put them on your Chromebook or Android device, and then open those files within Google's Chrome browser. This way you.