Under Agency detail, the post email address is an email address where the Agency can receive the Post emails containing the Invoices.
The From email address is the address from where the Agencies messages are sent out. For example: a Candidate has forgotten their log in details. On the Candidate Entry screen, there is a mail icon that has a tool tip saying Email Login Details. The candidate will receive their log in details from the from email address.
In the Client Entry page there is a section called Invoice Delivery with 3 options,
Email with link to download invoice
Email with attachment (Large documents may get rejected by mail clients)
Email to Agency to deliver via post (firstname.lastname@example.org)
Selecting the option Post will send these invoices to the Post email address.