The first method is as follows:
1) In the Google Cloud Console(GCP), the “hamburger-icon” on the top left corner of the screen, select the IAM & Admin under Products. (You must be logged in)
2)Click on Settings, if you had created a single project then it will be only be shown, click on Shut Down to delete the project.
The second method is as follows:
1)Click on the Settings and Utility options, the three-dotted icon on the top right corner on the screen.
2)Click on Project Settings, you will be taken to the Settings option under IAM & Admin, click on Shut Down to delete the project.
Note that deleting a project from the GCP releases all the resources used within the project. It releases all the VM instances, Storage(Buckets), Memory, Application, Firewall Rules, VPC network, etc that you created.
Kindly Make sure that you must have disabled billing on the project. Furthermore, the time it takes to delete a project may differ based on the number of services in use within the project.