PHPMailer is a powerful and flexible email-sending library for PHP. It enables developers to effortlessly send email messages via SMTP, mail(), or sendmail, with support for features like attachments, HTML emails, SMTP authentication, and more. With PHPMailer, you can easily integrate email functionality into your PHP applications, whether you're building simple contact forms or complex email systems. It's actively maintained, widely used, and offers comprehensive documentation, making it a top choice for handling email communications in PHP projects.