If you also want to work with other workflows such as leave approvals or travel approvals, the Professional plan is the one for you because it also offers standalone workflows.
ApprovalMax for Xero
This subscription covers approval workflows for Xero items such as Bills, Sales Invoices, Purchase Orders, Credit Notes. Generic workflows not related to Xero items are not supported.
ApprovalMax for QuickBooks Online
This subscription covers Purchase Order approval workflows for QuickBooks Online. Generic workflows not related to QuickBooks items are not supported.
ApprovalMax Professional Plan
This subscription supports workflows for any finance matter, including flows for the available integrations. As an example: with this plan, an investment company can set up approval workflows for Xero Bills as well as for Cash Calls that have nothing to do with Xero.