When a transaction posted, it updates the relevant accounts such as receivable and payable, stock on hand and prevents others from modifying the accounting entry.
A posted invoice will show in the "Payment on Invoices" list of a Receipts or Payment transaction, which allows the user to knock off against the payment.
Before you save a transaction, you can post it by clicking the POST icon next to the OK button or do it in a batch form. MoneyWorks store all the unposted transactions in the Unposted transaction list. From the Unposted transaction list, highlight those or all the transactions which you like to post and click the POST button.
You may consider backing up the file before posting and restore the file if there is a mistake. Rollback is another alternative which you can consider. Rollback if a mistake has discovered immediately after posting.
Posting helps prevent others from modifying it, especially when the financial report has printed. You can use "Cancel Transaction" (reverse an entry) if a mistake has discovered some time after posting.
Posting is important. You should do it regularly.
For more information on posting transaction, you can refer to page 99 of the MoneyWorks v7 User Guide.