I am using a premium theme and few plugins all are need to update. Previous when I update my theme I lose all of my customization. How can I update my theme and plugins so that plugin and theme customization unchanged.
Did your customizations include changing the source code in the theme/plugin files? If yes, then you cannot update without loosing them. Instead you can use the child theme approach. Or you can make a plugin, that makes changes to another plugin or theme, which is harder than just changing the source files and you do not have full control, but then you can update without loosing the changes.