The preferred way to grant individual (or group) permissions would be to add files under /etc/sudoers.d
This separates local changes from the default policy and saves time in case the distribution sudoers file changes.
To make the currently logged-in user a sudoer and sudo not prompt them for a password, use
echo "$USER ALL=(ALL:ALL) NOPASSWD: ALL" | sudo tee /etc/sudoers.d/$USERthis will create a file called /etc/sudoers.d/$USER (where $USER is the username of the user that you were logged in as when you ran that command), making it clear which users are granted permission.
If you want to do that for a different user, just replace both instances of $USER with some other username in the above command.
echo "otheruser ALL=(ALL:ALL) NOPASSWD: ALL" | sudo tee /etc/sudoers.d/otheruser
Similarly, one file can be used to manage multiple directives:
echo "username ALL=(ALL:ALL) NOPASSWD: ALL" | sudo tee -a /etc/sudoers.d/localSee /etc/sudoers.d/README and man sudoers for more information.