On every document and journal that can be posted, you can choose the Preview Posting button to review the different types of entries that will be created when you post the document or journal.
To preview G/L entries that will result from posting a purchase invoice
1. Create a purchase invoice.
2. On the Actions tab, in the Posting group, choose Preview Posting.
3. In the Posting Preview window, select G/L Entry, and then choose Show Related Entries.
The G/L Entries Preview window shows which entries will be created when you post the purchase invoice.