How to develop a composer package?

Question

PHP

Hello!
There is a project and a part of the functionality in which you want to put a package in the composer to use it in other projects. Creating a package / putting it on packagist.org was basically not difficult. But I had to create a separate project in the IDE, and each time upload a new version to git, and take it for testing into the project by updating dependencies.
What are the best prectices?
As an option, I see deploying git in the vendor folder itself. Will there be problems?
Thank you.

Answer 1

https://getcomposer.org/doc/05-repositories.md#path

Answer 2

https://packagist.org/about