Purchasing includes all the functions involved in the procurement of materials from the time that a need is identified until the time the material or service is received and used.
There a systematic determination of need, at the beginning of each year so major requirements for the year can be planned and budgeted for. This includes a review of whether the material or service is necessary or not and whether it is likely to represent value for money.
In the case of services required during the year the preferred cost effective method for each service provided is reviewed as a prerequisite to contracting for future services from the service provider.
Selecting suppliers/service providers, obtaining prices and full terms, utilising the tendering process (where necessary) cost price analysis, negotiation, purchase order or contract, expediting and contract administration.
This will include when and where to buy materials or services and in what quantities.
This is concerned with the receipt of materials, checking against order for quantity and quality, managing errors and discrepancies, recording, storing, authorising invoices for payment etc.