The websites for The Writers Place, Rocket Lawyer and SampleLettersWorld are some places to locate samples of a letter of agreement. These sites provide the writing guidelines as well.
The Writers Place gives a clear guideline on how to write an agreement letter. The site then gives a sample of an agreement letter between a company and a freelance writer.
Rocket Lawyer gives a step-by-step procedure showing how to write a sample letter, which is free for the first week of the membership trial. This platform uses an interactive tool to help write the letter, save it and sign it using a digital signature. SampleLettersWorld provides letter categories, sample letters, writing tips and recommendations of the best books to use. The site takes the visitor through the writing procedure of an agreement letter after choosing the desired type of agreement letter.