Because I don't know how much computer equipment and consumables you mentioned are used and how they are usually used, I can only give you a general suggestion.
1. The application department submits the purchase application.
2. The Information Department should check the equipment currently in use and give an evaluation of maintenance, upgrade or purchase (budget is given for your reference).
3. Non-budget departments should find several suppliers, give a list of materials and conduct public bidding. Computers and consumables are updated too quickly, so we should invite tenders regularly. )
4. The bidding results should be submitted to the President's office for approval.
5. The financial department shall execute the contract, make payment, check and accept it, and put it into storage.