Sharing models
If you have created useful models that may help other users, it would be good to share them with the community so that others don't need to reinvent the wheel.
As the saved Processing model is a single file in JSON format, the easiest way to share it with others is to send it to those who are interested in it, or upload the model file to any file sharing or hosting site and provide everyone with a link to this file.
A bit more complex—but at the same time, a very convenient and user-friendly—way is to publish your model in the Processing models and scripts community repository. This repository was created in the spring of 2014, and provides a centralized way to share Processing scripts and models among QGIS users.
To put your model into this repository, you need to fork the GitHub repository (https://github.com/qgis/QGIS-Processing), commit your model in your fork, and issue a pull request.
Tip
To learn more about Git, use one of the Packt's books, such as Git: Version Control...