Is the in flight emergency manual of a Boeing 737 Max 8 available to read online?
The in flight emergency manual is called the Quick Reference Handbook (QRH) and is in general not made publicly available by the manufacturer or airlines.

It is however possible to find quite a few online. Pages like smartcockpit.com have a lot of resources available. The Boeing 737 MAX is not mentioned on their page. A Google search for "737 max qrh" may help you find something.