Hi Emre ,
I wanted to answer the second part of the question. You can send e-mails and attach files to this e-mail by using the modules in the market place.
I am sending the documentation links required for this below .
(Note: Email module depends on Model reflection and Encryption modules, so you need to download them first). I hope it helps.
Regards
Ridvan
Related links :
https://docs.mendix.com/appstore/modules/email-with-templates
https://docs.mendix.com/developerportal/deploy/sending-email
https://docs.mendix.com/howto/data-models/working-with-images-and-files/
https://docs.mendix.com/refguide7/how-to-create-your-own-documents/
For more information about .ics file:
And here is the entity you might want.