Users who want to run the beta version of the latest operating system can go to beta.apple.com to install the betas on their devices. However, I would caution you that the betas are far buggier than what we had in iOS 12. So do that at your own risk.
If you can live with system crashes and many of the third-party apps not working properly then go ahead and install the betas. Otherwise, refrain from doing so. Also, once you go ahead and install the beta, please refrain from angrily targeting developers. They must be working really hard to get their app updated and working before the final release.
The main reason for becoming a beta tester is to get a glimpse of the future and help both third-party developers and Apple in improving the software by filing the bug reports. Please don't install the beta and then rage on Twitter. I have installed the betas on my primary devices because it's my work to do so. And even I get angry sometimes when things don't work properly. So, if you cannot handle the bugs, please don't install the betas.
If you can, just go to beta.apple.com and enjoy your new experience.