With debug mode turned on in WordPress, PHP errors will be displayed in plain text instead of being left invisible which is the default configuration.
To turn on debug mode, you will need access to your WordPress files via FTP, SFTP, SSH or your web host’s control panel. Then you’ll want to find the wp-config.php file and edit it. Once you’re in that file you’ll want to add a line in that says:
define( 'WP_DEBUG', true );
Then you should be able to try and visit a page on your site and instead of seeing an empty white screen, there should be errors on the screen.