How to Add reCaptcha Plugin to WordPress Site

One good plugin is Advanced Google reCAPTCHA.

How to Install Advanced Google reCAPTCHA Plugin

You can install the plugin from WordPress control panel or with WP-CLI tool.

Install With WordPress Control Panel

Go to WordPress control panel and Plugins > Add New.
Search Advanced Google reCAPTCHA and click Install Now.
After the installation you can activate the plugin by clicking Activate.

Advanced Google reCAPTCHA in Add Plugins view.

Install and Activate With WP-CLI Tool

Simply run this command: wp plugin install advanced-google-recaptcha --activate

How to Setup the Plugin

Google reCaptcha requires Site key and Secret key before you can use it. You can create the keys in Googles service.

Fields to add Site key and Secret key in WP Captcha settings.

When you get the keys, put those in the settings (Settings > Advanced Google reCAPTCHA). On the settings page, you can also change the plugin's settings to your liking.

List of site features where CAPTCHA can be enabled.

Now your WP login page, for example, is secured with I'm not a robot check box or in reCAPTCHA v3, the reCAPTCHA logo is displayed in the bottom right bar of the page when the page is protected.