Hi Karuppasamy
If you just want to customize the theme, then have a look at the following documentation: https://docs.moodle.org/dev/Themes
Regarding to 'pull the code', all the code is available to you if you have access to the server. Not sure what you mean here.
If you just want to customize the theme, then have a look at the following documentation: https://docs.moodle.org/dev/Themes
Regarding to 'pull the code', all the code is available to you if you have access to the server. Not sure what you mean here.