#step by step Process
>> Login github
>> Profile # right side of the page profile icon
>> Your repositories
>> Select repositories
>> Goto Settings # repository level settings
>> Delete this repository
>> Please type <repository name> to confirm.
gh repo delete url_of_the_repo // in terminal
gh repo delete [<repository>] [flags]
gh repo delete one --confirm
$ sudo apt install ppa-purge
$ sudo ppa-purge ppa:#repo-name