Remove all methods from the WordPress XML-RPC API.
The plugin removes all methods from the WordPress XML-RPC API. It is an alternative to just using the xmlrpc_enabled hook, because that is only used "To disable XML-RPC methods that require authentication".
Activating this plugin will disable pingbacks and trackbacks, because these rely on XML-RPC.
Step 1: Install it
Install this plugin by navigating Plugins -> Add New within your Admin dashboard, then searching for ' Remove XML-RPC Methods ', then click Install, then activate.
Alternatively you can head over here, download the plugin and then upload and extract it to your WordPress plugins folder.
Step 2: Use it
Use the plugin as shown in the below screenshots:
Reference
Read more here.