Functional Requirements - things it must or must not do.
Non-Functional Requirements - performance standards/quality, eg. security, scalability, usability, speed.
USER STORIES
As a business, I want to be able to send invoices, so that my invoices can reach outside of my local system.
Sending invoice to address (possibly email)
Files sent in correct format (UBL XML)
As a business, I want to know if my invoice was sent successfully so that I can make sure the invoice was sent or take further action.
Communication report with error or success
Report includes the type of error/s (eg. email address invalid, connection not etablished etc.)
Report also includes address, client, time/date
Readable communication report for humans to understand
As a business, I want to send intact invoices successfully so that my invoices are sent and not lost.
Corruption check
Files sent in correct format (UBL XML)
As a business, I want to be able to deliver invoices in different ways, so that I have flexibility and choice in reaching my clients.
Sending via SMS
Sending via Email
As a business, I want to be able to send to multiple recipients at once, so I don’t have to send it to them individually.
PURELY OPTIONAL
As a business, I want to be able to send multiple invoices at once, so that I don’t have to waste time sending them individually.
As a business, I want to know what invoices I’ve sent successfully so that I can keep track of which invoices have been delivered.
...
...
USE CASE
After requesting an invoice and it being created, I click send invoice
I pick the delivery method (Email/SMS/SFTP) and input the details
I click ‘send invoice’ and the system send the invoice to the addressee
If the invoice is sent successfully, I receive a Communication Report with success and details
If the invoice is sent unsuccessfully, I receive a Communication Report with related errors and details, and am taken back to the sending page.
...