Best Practice in Entering Purchases of Non-stock Items

In the process of purchasing we raise purchase receipts and then Purchase invoices for items for which we maintain stocks. What is the best practice for entering purchase of non-stock items/services etc.? Sometimes it is not important to register description of these items and only requirement is to debit or credit against the desired expense account.

You should create Purchase Order and Purchase Invoice for non-stock item. And you should maintain item code for those to get proper MIS report.