Hi Nisha,

Have you followed the mendix guide:

Creating Your Own Documents: https://docs.mendix.com/refguide/creating-your-own-documents/

In this doc. you can see the basics steps:

• Define in your Model a Entity with generalization of <FileDocument> https://docs.mendix.com/refguide/creating-your-own-documents/#41-domain-model
• Create a Custom Document Template https://docs.mendix.com/refguide/document-templates/
• Create a Microflow to generate your Document, basically this activities: 
  • Create a New “OrderFileDocument”
  • Retrieve others associated data
  • Generate Document (PDF)
  • Download “OrderDocument”
• From your pages call this Microflow with a “Order” as input
• Done, the file should be download soon.

To send to Email, you will need another Module, like : https://docs.mendix.com/appstore/modules/email-with-templates/

• After you downaload this modulo from Market place
• You have to setup a Email Template and your SMTP Id stuff
• Follow the sample Microflow in it to send a mail!
• 

I hope this helps!

Best regards