If the version of HPLIP in the Ubuntu repositories is outdated, you can download the latest version directly.
Although Ubuntu 18.04 is old (released April 2018), you can compile the latest HPLIP manually. hp laserjet m1136 mfp driver for ubuntu 18.04
After installing, restart CUPS with sudo service cups restart and add the printer via the Ubuntu Settings > Printers menu. If the version of HPLIP in the Ubuntu
Newer HPLIP may drop support for Python 2 (Ubuntu 18.04’s default). You may need to install Python 3.6+ from the deadsnakes PPA. hp laserjet m1136 mfp driver for ubuntu 18.04