If your store or company has employees who input purchase transactions and always need verification or approval from the Supervisor/Manager, there is a configuration setting that you can set up to activate the approval every time a purchase transaction is inputted. The objective of activating this 2 steps approval is to hold purchase transactions made by employees to be re-checked or re-validated by their Supervisor/Manager. To do this setup, you can follow the steps down below:
I. Configuration
Step 1. Go to Setup Menu - More Menu - Module

Step 2. Tab Buy - Workflow Buy "Approve" - Save

II. Set Roles User
Step 1. Go to User Menu - Select Group User

Step 2. Roles Buy - More Permission - Approval - Save

III. How To Use
When the config has been activated all you have to do is purchase the item from the supplier as usual using the buy menu.
Step 1. Go to Buy Menu
Make a purchase as usual then press pay to process it.

Step 2. Orders - Supplier Bill
After you make a purchase, you can check the purchase transaction that you have made to the Orders menu and then to the Supplier Bill tab. After config is activated, on the Supplier Bill list you will be able to see a new column addition that explains the status of the purchase.

Step 3. Click Invoice Number of Supplier Bill - Approve
You can approve the purchase submitted to you by clicking on the invoice number to make an "Approve" or approval.

Step 4. Approve Successful
After successfully approving the status your invoice will change to "Approved".

Display Supplier Bill Invoice:

*Important Note: You can receive stocks and receive payment after invoicing is approved.
You might also like to read this article:
If you want to make a Purchase Return, you can read the article here: Purchase Return
To change the default payment to Later on the BUY menu, you can check this article for the setup: How to Select Default Payment in Buy.
For COGS calculation in DealPOS, we have several calculation methods, including Average, LastOrder, and Manual. To set up, the COGS Calculation, go check this article: Setting Up Product's COGS Calculation.