Mailx command to send the email to gmail account with content type as Content-Type: text/html

I have installed the mailx , on Red Hat Enterprise Linux Server release 7.2 Am able to send the mail successfully, with following command. **echo -e "Body content goes here ..." | mailx -v -r "sendermail_id@x.com" -s "subject content goes here" -S smtp=smtp://x.x.x.x receivermail_id@.com** Above command sends mail with plain text in the body **I want a command wherein i can send mail with html type content in the mail body. like bold letters, font colors......How do i do??? any help will be appreciated.**