Google reCAPTCHATo prevent a spam, you can use captcha. Google reCAPTCHA is a good option. It is free and pertinent while submission.
InstallationYou can install Google reCAPTCHA plugin using 2 different ways:
How To Get Google reCAPTCHA On Submission Form?First of all, you need to register on reCAPTCHA website to get reCAPTCHA keys. For that, you have to name your site and enter the domain.
Customization: Overriding/Customizing The Template FilesFor overriding or customization template files can be found in the wp-event-manager-google-recaptcha/templates/ directory. To override a template file, first you need to create directory “wp-event-manager-google-recaptcha” under your theme folder and copy the template file to “/wp-content/yourtheme/wp-event-manager-google-recaptcha/” directory. Your theme will use all the template files from the “/wp-content/yourtheme/wp-event-manager-google-recaptcha/” directory instead of the plugin’s template file (/wp-content/plugins/wp-event-manager-google-recaptcha/).
- event-google-recaptcha.php template file lists the user’s alerts.
Remember: if you have overrided template file and plugin frequently updating then you need to sync template file with new updates from the plugin’s template file for better functionality and new features.