Here We will learn about Max Qty Allowed on Items Customization while update cart page.
We have to create a new module if you already not created, after that follow the steps that describe in the post.
#1 : We need to register the Plugin in magento 2.
add the following code in “etc/frontend/di.xml” of your module
#2 : Add the following code in your plugin file.
Namespace\Modulename\Plugin\Qtycheck.php
#3 : Now you need to run the dependancy Setup in your console or terminal command.
php bin/magento setup:di:compile
#4: Flush the cache in your console or terminal command
php bin/magento cache:clean && bin/magento cache:flush