In case you want to prevent scammers in your Magefan blog comments, protect your website and personal data and improve security in general you can use reCaptcha. 

The following steps to enable the Magefan blog comments reCaptcha:

1. Make sure you have the Magento 2 Blog Extension reCaptcha installed on your Magento Instance.

2. Navigate to Stores > Configuration > Security > Google reCaptcha and find Frontend section there.

Magento 2 Google ReCaptcha Configuration

3. Enable Blog Comments reCaptcha in the Use in Magefan Blog Comments field.

Magento 2 Blog Comments Recaptcha

Once you finish don't forget to Save the configuration and flush Magento Cache.