" 1. Letters must be legible (large print) and handwritten. No worries if you’re not artistic– make your card as what you’d like to receive.
2. Avoid religion, if possible. Your letter should resonate with anyone.
3. Exclude the date (day, month, and year).
4. Embrace creativity! Recipients love it when the letters are personal. We encourage you to make your letters detailed, thoughtful and heartfelt.
5. Be kind and thoughtful (more than talking about yourself). This is a one-way letter exchange, meaning you will not receive a letter back, so remember that no reciprocation attached is part of the beauty of your act of kindness, and the recipients don’t feel burdened by feeling obligated or being unable to respond. "
Click the link for example letters as reference: https://lovefortheelderly.org/letters