diff --git a/extensions/swiftmailer/yii/swiftmailer/Message.php b/extensions/swiftmailer/yii/swiftmailer/Message.php
index 89a871d..cecb61f 100644
--- a/extensions/swiftmailer/yii/swiftmailer/Message.php
+++ b/extensions/swiftmailer/yii/swiftmailer/Message.php
@@ -45,6 +45,7 @@ class Message extends BaseMessage
 	public function setCharset($charset)
 	{
 		$this->getSwiftMessage()->setCharset($charset);
+		return $this;
 	}
 
 	/**
@@ -62,6 +63,7 @@ class Message extends BaseMessage
 	{
 		$this->getSwiftMessage()->setFrom($from);
 		$this->getSwiftMessage()->setReplyTo($from);
+		return $this;
 	}
 
 	/**
@@ -78,6 +80,7 @@ class Message extends BaseMessage
 	public function setTo($to)
 	{
 		$this->getSwiftMessage()->setTo($to);
+		return $this;
 	}
 
 	/**
@@ -94,6 +97,7 @@ class Message extends BaseMessage
 	public function setCc($cc)
 	{
 		$this->getSwiftMessage()->setCc($cc);
+		return $this;
 	}
 
 	/**
@@ -110,6 +114,7 @@ class Message extends BaseMessage
 	public function setBcc($bcc)
 	{
 		$this->getSwiftMessage()->setBcc($bcc);
+		return $this;
 	}
 
 	/**
@@ -126,6 +131,7 @@ class Message extends BaseMessage
 	public function setSubject($subject)
 	{
 		$this->getSwiftMessage()->setSubject($subject);
+		return $this;
 	}
 
 	/**
@@ -142,6 +148,7 @@ class Message extends BaseMessage
 	public function setText($text)
 	{
 		$this->setBody($text, 'text/plain');
+		return $this;
 	}
 
 	/**
@@ -150,6 +157,7 @@ class Message extends BaseMessage
 	public function setHtml($html)
 	{
 		$this->setBody($html, 'text/html');
+		return $this;
 	}
 
 	/**
@@ -209,6 +217,7 @@ class Message extends BaseMessage
 			$attachment->setContentType($options['contentType']);
 		}
 		$this->getSwiftMessage()->attach($attachment);
+		return $this;
 	}
 
 	/**
@@ -224,6 +233,7 @@ class Message extends BaseMessage
 			$attachment->setContentType($options['contentType']);
 		}
 		$this->getSwiftMessage()->attach($attachment);
+		return $this;
 	}
 
 	/**
diff --git a/framework/yii/mail/MailerInterface.php b/framework/yii/mail/MailerInterface.php
index 60e231c..1ed9256 100644
--- a/framework/yii/mail/MailerInterface.php
+++ b/framework/yii/mail/MailerInterface.php
@@ -10,6 +10,8 @@ namespace yii\mail;
 /**
  * MailerInterface is an interface, which any mailer should apply.
  *
+ * @see MessageInterface
+ *
  * @author Paul Klimov <klimov.paul@gmail.com>
  * @since 2.0
  */
diff --git a/framework/yii/mail/MessageInterface.php b/framework/yii/mail/MessageInterface.php
index 301a8d1..e2418d3 100644
--- a/framework/yii/mail/MessageInterface.php
+++ b/framework/yii/mail/MessageInterface.php
@@ -9,6 +9,19 @@ namespace yii\mail;
 
 /**
  * MessageInterface is an interface, which email message should apply.
+ * Together with application component, which matches the [[MailerInterface]],
+ * it introduces following mail sending syntax:
+ * ~~~php
+ * Yii::$app->mail->createMessage()
+ *     ->setFrom('from@domain.com')
+ *     ->setTo('to@domain.com')
+ *     ->setSubject('Message Subject')
+ *     ->renderText('text/view')
+ *     ->renderHtml('html/view')
+ *     ->send();
+ * ~~~
+ *
+ * @see MailerInterface
  *
  * @author Paul Klimov <klimov.paul@gmail.com>
  * @since 2.0
@@ -18,6 +31,7 @@ interface MessageInterface
 	/**
 	 * Set the character set of this message.
 	 * @param string $charset character set name.
+	 * @return static self reference.
 	 */
 	public function setCharset($charset);
 
@@ -27,6 +41,7 @@ interface MessageInterface
 	 * You may pass an array of addresses if this message is from multiple people.
 	 * You may also specify sender name in addition to email address using format:
 	 * [email => name].
+	 * @return static self reference.
 	 */
 	public function setFrom($from);
 
@@ -36,6 +51,7 @@ interface MessageInterface
 	 * You may pass an array of addresses if multiple recipients should receive this message.
 	 * You may also specify receiver name in addition to email address using format:
 	 * [email => name].
+	 * @return static self reference.
 	 */
 	public function setTo($to);
 
@@ -45,6 +61,7 @@ interface MessageInterface
 	 * You may pass an array of addresses if multiple recipients should receive this message.
 	 * You may also specify receiver name in addition to email address using format:
 	 * [email => name].
+	 * @return static self reference.
 	 */
 	public function setCc($cc);
 
@@ -54,24 +71,28 @@ interface MessageInterface
 	 * You may pass an array of addresses if multiple recipients should receive this message.
 	 * You may also specify receiver name in addition to email address using format:
 	 * [email => name].
+	 * @return static self reference.
 	 */
 	public function setBcc($bcc);
 
 	/**
 	 * Sets message subject.
 	 * @param string $subject message subject
+	 * @return static self reference.
 	 */
 	public function setSubject($subject);
 
 	/**
 	 * Sets message plain text content.
 	 * @param string $text message plain text content.
+	 * @return static self reference.
 	 */
 	public function setText($text);
 
 	/**
 	 * Sets message HTML content.
 	 * @param string $html message HTML content.
+	 * @return static self reference.
 	 */
 	public function setHtml($html);
 
@@ -81,6 +102,7 @@ interface MessageInterface
 	 * @param array $options options for embed file. Valid options are:
 	 * - fileName: name, which should be used to attach file.
 	 * - contentType: attached file MIME type.
+	 * @return static self reference.
 	 */
 	public function attachContent($content, array $options = []);
 
@@ -90,6 +112,7 @@ interface MessageInterface
 	 * @param array $options options for embed file. Valid options are:
 	 * - fileName: name, which should be used to attach file.
 	 * - contentType: attached file MIME type.
+	 * @return static self reference.
 	 */
 	public function attachFile($fileName, array $options = []);