The following command will give sudo access to a user on a linux machine:
sudo printf "myuser ALL = NOPASSWD: ALL\n# User rules for myuser\nmyuser ALL=(ALL) NOPASSWD:ALL\n" | sudo tee /etc/sudoers.d/myuser > /dev/null && sudo chmod 440 /etc/sudoers.d/myuser
Where myuser is the username you are granting privileges to. The command will also apply the correct file permission to the newly created file in /etc/sudoers.d directory