Hello Montassar!
First of all I'd just like to clarify that Blockly and Scratch are different things =) Blockly is targeted at developers (like you!) that want to build things like Scratch, which are targeted at people that want to use blocks to code.
As for your main question, Blockly is a web library, so if you want to use Blockly to build something you upload to the play store, the best way to do that is to use
electron to build a cross-platform app.
I hope that helps! If you have any further questions please reply!
--Beka