WordPress: https://wordpress.org/
Register Plugin
Developments should be made in accordance with the plugin guidelines before registering the plugin.
Plugin Creation: https://codex.wordpress.org/Writing_a_Plugin
plugin registration: https://wordpress.org/plugins/developers/add/
plugin Promotions: https://codex.wordpress.org/Plugin_Submission_and_Promotion
plugin Guide: https://developer.wordpress.org/plugins/wordpress-org/
Register Theme
You should develop the theme according to the guidelines set by WordPress before registering it.
Theme Guide: https://codex.wordpress.org/Theme_Development
Theme Registration: https://wordpress.org/themes/upload/