This module let you add css and javascript code in any theme. It also support Jquery.
Magento 2.x
-Install by Composer :
You can install the module by Composer (If your server supports Composer). Please go to the Magento folder and run the command: composer require hashcrypt/additional-css-js
-Install by uploading files:
Download the zip file and unzip the plugin. Now create folder app/code/Hashcrypt/CssJs and copy all files which you have downloaded to that folder. Now run below commands to install module, php bin/magento setup:upgrade php bin/magento cache:flush
Go to admin panel > Stores > Configuration > Hashcrypt Technologies > Additional Css-Js Enter custom style and script then save the configuration. Flush the cache if cache is enabled.