You can test invisible recaptcha by using Chrome emulator.
You will need to add a new custom device (BOT) in developer tools, and set User Agent String to Googlebot/2.1 on Desktop. Then use the new BOT device when testing on your site to trigger the recaptcha authentication.
Note: ReCaptcha v3 will still let the google bot pass as it has a score of 0.9 when emulating in Chrome.
V2 INVISIBLE
In this case just use Incognito or Private browsing to see it works.
Here is the testing link where ReCaptcha is working:
https://www.google.com/recaptcha/api2/demo?invisible=true
Please give the credits to the guys in comments below.