The first step to getting your exemption letter is to donate, and become an online member of the Church.
The donation threshold for membership is $20/mo, or $240/year.
The second step to getting the vaccine mandate exemption is to fill out this form
Make sure to include your Name (both first and last), your complete mailing address, your phone number, and your email address. Also list the name the donation was under, if not your own name.
You should receive within 48 hours.