You can create your sales receipt design with ZebraDesigner software and save it as ZPL commands in a text file . For the case you will need to customize your design you can find comprehensive ZPL programming manual here:
To print your label on Zebra printer you can use Link-OS Multiplatform SDK which has support for Android. You can download and install SDK. Then you will find sample android studio projects inside of installed SDK. Also there are documentation on Link-OS SDK for Android and Link-OS SDK for Android BLE.
Although Link OS SDK is able to support some legacy printers with lack of some features, I would recommend you to go with Link-OS printers. It could be ZQ320:
It is replacement model for legacy iMZ320 printer, which is discontinued:
Software Engineer, Kutir Mobility
Posted on behalf of Zebra Technologies