This note are about Raspbian based on Debian 9 Stretch, which uses systemd.

Using raspi-config you can go to the menu Boot Options ⇒ Desktop / CLI, where you can choose:

• B1 Console
• B2 Console Autologin
• B3 Desktop
• B4 Desktop Autologin

Beware that you should execute raspi-config after a sudo su, otherwise options B2 and B4 cannot determine the non-root user to be used. You can force that user setting the shell variable:

export SUDO_USER=pi

The Desktop Autologin is performed with Lightdm Desktop Manager, configuring the file /etc/lightdm/lightdm.conf:

autologin-user=pi

Choosing the Desktop Autologin will enable also a Console Autologin on the VT1, with the same non-root user. The config is obtained via a symlink:

/etc/systemd/system/getty.target.wants/getty@tty1.service ->
    /lib/systemd/system/getty@.service

and a configuration file /etc/systemd/system/getty@tty1.service.d/autologin.conf.