Letters of recommendation may be submitted online by your recommenders at any time after you start your online application. It is strongly recommended that you waive or decline to waive your rights of access to your letters of recommendation (using the online application system) BEFORE you start inviting recommenders to submit their information for you.
Describe how you know the person. Give some context for your recommendation. Let the reader know how you met them, how you worked together, and your basic qualifications.