EmailDLL Online Manual
Parameters: TextLine: the line of text to add to the message.
Returns: Success or Error Status
This method adds text to the message after any previously added text, and before any message file you might add. You can add text in two styles. If you prefer to have your own line separations in the email text, then call this method multiple times, once for each line of text in the message. You can also call this method with a single very long section of text, and that will be added as well. You shouldn't have any trouble with quote marks, but be very careful with any extended characters. That is, those whose ASCII value is above 126 (7E hex). Email is, After all, restricted to seven bits of transmission.
To add a blank line to your message text, use either an empty string, or a single space as the TextLine argument.