What PDF reader are you testing this with? PDF forms will only reliably work with Adobe Acrobat and Adobe Reader? You're probably trying to use a browser, or a sub-standard PDF reader like Preview on the Mac.
For your intended workflow, you need to configure/distribute the PDF from Acrobat, to then have a recipient complete form, and then return PDF with response data.
I am using Foxit Reader as PDF reader. But PDF opens correctly.
However, when I try to send those answers, PDF is not attached.
I've already tested using Adobe Acrobat but it is not the case, because we need to open it using Google Chrome.
Do you understand me? I don't know if I were clear, because English is not my first language, so I'm trying to express myself.
Then, when I click "send email" it opens a blank email and it does not carry all data we've created on the form.
When I open with Adobe Acrobat or Foxit Reader it works, the problem is when opening with Google Chrome or other browsers.
Yes, that’s clear.
It won’t work in a browser. That’s just a fact of life.
Thank you Bob for being honest.
I think you're right. I've found another way.
It's been quite a few years since I did a PDF form (had to do it all in Acrobat at the time), but my recollection is that the submit button sent only the form data to be processed in a database you set up for the purpose, not an attached PDF. I don't know if that's still true, but you might want to check the documentation to see.
The PDF needs to be saved with Extended Rights. Then the PDF can make a return trip with entered responses emailed to the address set in the submit button. Saving Extended Rights is configured in Acrobat, not Indesign.