System hang - Finding and reporting error details

My system hangs randomly, seems to be when just browsing the web. I basically have to do a manual shutdown by turning off PC.

Release 19.04 (Disco Dingo) 64-bit
Kernel Linux 5.0.0-15-generic x86_64
MATE 1.20.4
67.0 (64-bit) Firefox Quantum Plugins = DuckDuck go privacy essentials, LastPass and ExpressVPN.

Is there anyway to trouble shoot this or at least find information to report to someone such as log files?

thanks
Jon