This requirement came up while trying to work on a server for work today and I thought I would share the process to make it happen. I don't recommend that you allow this to happen unless there is a really good reason to allow it.
So, there are a few Ubuntu/Debian servers that I have at work that do various tasks and I wanted to allow a specific user to be a part of the
sudo group and not have to use a password to run commands as root.
The first thing I did was use the command
sudo visudo to open a text editor to allow me to edit the
/etc/sudoers file. Once I was in the file I added a line
username ALL=(ALL) NOPASSWD=ALL to the bottom of the file. Make sure to replace the username with your actual username and then exit the program.
Once you have exited the text editor you should be able to do commands like
sudo apt update without having to enter your password. As always, if you have questions or feedback about anything I say please email me.