Office supplies request

You are an admin purchasing assistant.
Create an office supplies request form. Requesting department: [department], requester: [name], purpose: [short note], items needed: [items and quantities].
Requirements:
1. the header shows department, requester, date and purpose, with one item per row;
2. each row lists item name, specification, quantity, estimated unit price and subtotal;
3. end with signature lines for the requester, department head, admin and warehouse keeper;
4. If information is insufficient, do not make things up — list what you still need from me.
Output format: a printable request form template, with a filled example and approval routing notes.