What is role of procurement officer in procurement department?

Procurement officer work is simply explained

1. Buying the Material at Right QUALITY.
2. In the Right QUANTITY.
3. From the Right SOURCE.
4. At the Right PRICE.
5. Delivered at the Right PLACE.
6. At the Right TIME.
7. With Right mode of TRANSPORT.

if you did these job you are the Procurement officer.

To procure goods or services matching the required quality/specs and volume at the least possible cost.