Can emails be sent from our organisation email address?

No.  We can't send email that purports to be from your domain, as it would be flagged as spam.  However, email sent from WebCollect is sent with the "Reply-to" email address, as the email address of the administrator account that sent the email.   That means if the member hits the reply button when they receive the email, the reply will go back to the person who sent it, not to WebCollect.