How can I allow form to upload and send fiels?

To allow file uploads you need to do:

1) On your form add file field, for example:

Person who submit form will use this field to attach file

2) In your email template in headers section add:

or you can pack it in zip if you need:


After this your form will be able to upload and send file attachments.
For example you can see 'file-upload-form-with-different-file-checks' from sample forms.