Local development

Now on my ubuntu i install Docker and run shopware local , and install phpstorm , but which file i should open and edit in env.
Q2: after playing and edit on the theme localy , i will upload it on github and upload on my online server ?

Maybe you should take a look at Shopware 6 and Home - Shopware Developer to get a better understanding of Shopware. All your questions are answered in these documentations.

The .env (main directory) is you configuration file. If you have used the zip file to install Shopware, you have to enter your SQL server data, URL, e.g. If you have used the composer installation, the installer should have asked for these information.

It is completely up to you how you deploy your installation. You can use a ftp, ssh, or git(hub), etc.