Hi Ramya,
Thanks for asking your question on the forum. In order to send e-mails, you will need to have an e-mail server that you can use. Normally, this is the SMTP server of your company. Alternatively, you could use something like Gmail.
https://docs.mendix.com/appstore/modules/forgot-password/
https://docs.mendix.com/appstore/modules/email-with-templates/
Hopefully, this helps!