To delete a PowerApps environment, log into https://admin.powerapps.com/ and go to Environments, then select the environment. Click Delete:

Enter the name of the environment to delete:

You will see:

The environment will then be deleted.
THANKS FOR READING. BEFORE YOU LEAVE, I NEED YOUR HELP.
I AM SPENDING MORE TIME THESE DAYS CREATING YOUTUBE VIDEOS TO HELP PEOPLE LEARN THE MICROSOFT POWER PLATFORM.
IF YOU WOULD LIKE TO SEE HOW I BUILD APPS, OR FIND SOMETHING USEFUL READING MY BLOG, I WOULD REALLY APPRECIATE YOU SUBSCRIBING TO MY YOUTUBE CHANNEL.
THANK YOU, AND LET'S KEEP LEARNING TOGETHER.
CARL
