A free program for Android, by Andrej Shadura.
This app is designed for Android devices that can connect to a portable printer either via a Bluetooth or USB connection. It will allow you to print directly from your phone, tablet, or laptop to the printer. It is compatible with a wide range of printers, from the most common to little-known brands that you may find in shops or on Amazon.
It is designed to be easy to use, and the main screen allows quickly setting up the app. Once you've selected the settings, you can customize them to match your needs.