Add to sudoers

From https://linuxize.com/post/how-to-add-user-to-sudoers-in-ubuntu/

Log in as root with root password

su -

Add user to sudoers

usermod -aG sudo username

Add user to sudoers

echo "username  ALL=(ALL:ALL) ALL" | sudo tee /etc/sudoers.d/username

Disconnect and reconnect to apply changes

exit

Now you can use sudo

sudo apt update