There is no Zotero Settings in my side, so I can't fine Zotero's features
                    I want to find Tools to create add-on but I can't find this tab. 
https://s3.amazonaws.com/zotero.org/images/forums/u18322770/dddqu9wkur34zcrydp6z.png
                
                            https://s3.amazonaws.com/zotero.org/images/forums/u18322770/dddqu9wkur34zcrydp6z.png
 Upgrade Storage
 Upgrade Storage
(Add-ons are now called Plugins in Zotero. And I assume you want to add a plugin, not create one.)