username is not in the sudoers file

Hello guys, If you are using the Linux operating system, especially the Debian 12 operating system, after installing the Debian 12 OS, if you want to install any software or packages or bundle, or if you want to update or upgrade the system by terminal you will face this error "username is not in the sudoers file" . So today I will show you how you can fix this error.

You can see I also have same error

To fix this error follow the steps. Open your terminal type "su" and press enter then type your admin password then press enter.

Now type "nano /etc/sudoers" and press enter.

You will see this type of interface

Now find this line "# User privilege specification" and enter your username like this.

For save the file press CTRL + X then type Y then press enter

That's all, issue has been fixed.