For RPM-based distributions:
A few hundred packages downloaded. He ran the GUI setup tool: hp laserjet pro 400 m401dn driver linux
sudo apt update && sudo apt upgrade hplip hp laserjet pro 400 m401dn driver linux
sudo apt update sudo apt install hplip hplip-gui sudo hp-setup hp laserjet pro 400 m401dn driver linux
. This means you get a complete desktop environment experience on Linux that matches Windows/macOS functionality. Key Capabilities Provided by HPLIP: Real-Time Status & Alerts : Through the hp-toolbox
However, "supported" does not mean "plug-and-play" for every distribution. You need the correct driver version and configuration.
Open a browser to http://localhost:631 .