There are a number of resources on the Web for this, but most are outdated or take the process further than I wanted. To be clear, I don’t want to disable the Pi’s desktop or block the user from using Chrome. I just want the Pi to default to opening Chrome, full screen, to a specified Website URL.
Starting with a Raspberry Pi loaded with Raspbian as is the recommended configuration. You must be connected to the network/internet and I usually turn on SSH and VNC so I can control the device remotely. (You can enable these by clicking Menu > Preferences > Raspberry Pi Configuration > Interfaces)
Now that that is established here is what you need to do to get Chromium to open full screen to a Website of your choice. Open Terminal and type the following.
That brings you into the hidden .config directory in the pi users home directory.
sudo mkdir -p lxsession/LXDE-pi
Sudo might not be needed here but this command creates the
sudo nano lxsession/LXDE-pi/autostart
This command opens the nano text editor with a file named autostart that we will save after typing or pasting the following content.
@lxpanel --profile LXDE-pi @pcmanfm --desktop --profile LXDE-pi #@xscreensaver -no-splash point-rpi @chromium-browser --start-fullscreen --start-maximized https://google.com/
Change the Website URL to whatever you like.
If you don’t already know click Ctrl+X to exit the editor. You will be asked to save. Type Y and then just accept the autostart file name by clicking enter.
The above code still works as of 12/5/2021 as I just set up the same item on a new Pi 4. Robert is correct that the URL must be on the same line.