How can I add "X-Frame-Options" header for my WordPress site?

Question

How can I add "X-Frame-Options" header for my WordPress site?

Answer

1. Navigate to the directory where WordPress is installed using cPanel / Home / Files / File Manager or via SSH.

2. Create a copy of the original wp-config.php file using File Manager or the following command:

   # cp -v wp-config.php{,.$(date +%s).bak}

3. Open the wp-config.php file for editing using File Manager or your preferred command-line text editor (such as vi or nano for example).

4. Locate the following line in the wp-config.php file:

   /* That's all, stop editing! Happy blogging. */

5. Add the following line below the line mentioned in step 4.

   header('X-Frame-Options: SAMEORIGIN');

   Note: The above function can be used to apply other headers besides X-Frame-Options as well.

6. Save and close the wp-config.php file.

7. Use the curl command to test if the header was added successfully:

   # curl -IL example.com
   HTTP/1.1 301 Moved Permanently
   Date: Tue, 13 Apr 2021 06:19:32 GMT
   Server: Apache
   X-Powered-By: PHP/7.4.1  6
   X-Frame-Options: SAMEORIGIN
   X-Redirect-By: WordPress
   HTTP/1.1 200 OK
   Date: Tue, 13 Apr 2021 06:19:37 GMT
   Server: Apache
   X-Powered-By: PHP/7.4.16
   X-Frame-Options: SAMEORIGIN

   Note: Replace the "example.com" placeholder with your actual domain name. You should see the header added via the wp-config.php file (X-Frame-Options: SAMEORIGIN) in the output of the curl command as shown in above example output.