How to create moodle local plugin

To create local plugin you can follow following folder structure according to Moodle documentation (https://docs.moodle.org/dev/Local_plugins)-

local/
     yourplugin/
       db/
         access.php
         install.php
         install.xml
       lang/
         en/
           yourplugin.php
       index.php
       settings.php
       version.php

Custom /local/ plugins

Local plugins are used in cases when no standard plugin fits, examples are:

• event consumers communicating with external systems
• custom definitions of web services and external functions
• applications that extend moodle at the system level (hub server, amos server, etc.)
• new database tables used in core hacks (discouraged)
• new capability definitions used in core hacks
• custom admin settings
• extending the navigation block with custom menus