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.
Use a business closing and sign your name. Above all, be professional. If the you’re sending a physical letter, print it out and sign it by hand. Otherwise, just typing your name will do.