DistroTest is a website that allows users to test a variety of different Linux distributions directly in their web browser, without the need to install them on their own computer. This can be useful for trying out different distributions to see which one might be the best fit for you, or for testing out specific features or configurations without having to set up a virtual machine or dual-boot your computer.
To use DistroTest, you'll need to have a web browser and an internet connection. Simply go to the DistroTest website (https://distrotest.net/) and choose the Linux distribution that you want to test from the list. You'll then be presented with a terminal window where you can enter commands and interact with the distribution as if you were using it on your own computer. Keep in mind that because you're running the distribution in a web browser, you may not have access to all of the features and functionality that you would if you were running it natively on your own computer.
DistroTest is free to use, although you may see some ads on the website. You can also support the development of DistroTest by making a donation through the website.