Sample Retainer Agreement. The terms in your document will update based on the information you provide.How to fill out the Legal Retainer Agreement Template? You may find the pdf form available on this page. Additional forms may be found at the Superior Court's Law Library Resource Center website. Writing a retainer agreement requires a retainer agreement template that you can download from this website. The sample agreement will include a blank agreement as well as a second copy with instructional call-outs containing suggestions on how to to fill it out. A fee retainer agreement a type is a contract where a client or customer pays in advance for professional services and work product to be specified later. Sample Fee Agreements. Xrays Complete series or Panoramic (Panorex) Only one per person, including panoramic film, in any 36 consecutive months.