Can Board members see paid invoices in the portal?

They should be able to, without asking, going back at least to the start of the current fiscal year and ideally further. A Board member who has to email a request and wait two days to see a backup invoice is not exercising oversight; they are filing a records request with their own vendor.

This is a genuinely useful discriminator between firms. Ask for a demonstration during the search: open the portal, pick a month, click through from a general ledger line to the scanned invoice image behind it. Some platforms do this in two clicks. Some cannot do it at all.

Ask how far back the history goes, whether the images come across in a transition, and whether every Board member gets access or only officers. Read-only access for all directors is normal and appropriate; a firm that restricts it to the treasurer is making a governance decision that is not theirs to make.

The wider question underneath is what a Board member can see and do without calling anyone. That answer varies more between companies than almost anything else they sell, and it is easy to test before you sign and impossible to change after.