The "Attachments" option can be found in some of the application's sub-menus and is useful when you want to store documents related to your transactions. In essence, Elorus works like cloud storage service and each file can reach up to 3MB in size. By pressing the "Attachments" button that exists within each record's page, you can upload as many files as you wish (one at a time), making sure they do not exceed this size.
This function is available:
for each contact
for each purchase or sales document, debit or credit
for each estimate
for each receipt / payment
Concerning Invoices and Estimates, attachments appear as an option when sending an email to the contact. That way your client can receive the invoice in pdf form. This means, that if you wish to include an attachment on the invoice you send to the customer, it needs to be uploaded prior to pressing the email button.
Especially for Bills, this feature is important because it allows you to store documents online from your suppliers to Elorus, in a digital form. This requires the vendor to send you an electronic document (PDF, image, etc.) or scan the printed invoices and then attach them to the purchase invoices. Note that this feature is different from the "receipt attachment" you may upload while adding a bill.
The projects can also contain attachments- you may share with team members assigned to each projects as well as your client provided you have given them the necessary access in portal.