How can I make sure Peachtree is posting to the right expense account in the Purchase/Receive Inventory Task screen?

 The Global Options (from the Menu bar, select Options, Global) store the setting whether to display the GL Accounts in the Accounts Payable task screens.  If you are hiding the GL Accounts, you can select the JOURNAL button to view the accounts Peachtree posts to “behind the scenes”.  If you need to change the account id, you can do so on this screen.

If you are not hiding the GL Accounts, you can see the account number on each row for the purchase invoice.  This account number defaults to the purchase account set up in the vendor file under Maintain, Vendors.  You can change the GL Account for any row on the purchase journal by selecting the GL Account field, then enter the correct account id or select the correct account id from the look-up list.