Set Magento 2 Mode Using CLI

Magento 2 comes pre-configured with a command that switches Magento 2 modes from developer mode to production mode. This not only facilitates the ease of use but also improves the overall security of the store as well. With this mode, we can set the ownership and file permissions appropriately. There is a small basic difference between the two modes, as explained below:

• Production mode has better execution because static view files are located in the bar/static directory due to code compilation.
• 
  
• Developer mode is used for internal development on a system already secured behind the firewall. Developer mode can be of real help when you are customizing your Magento store.
• 
  

Note: Developer and Production modes are set in env.php file this file locate in /app/etc/env.php

Read Complete Tutorial Here.