You mean Mexican traditions?
This sentence should be:
Ustedes mandan cartas a su abuela cada mes.
Translation:
You(formal) send letters to your grandma each month.
Ustedes- you(formal)
Mandan-send
Cartas- letters/cards
A su- to your
Abuela- grandma
Cada- each
Mes- month
The sentence you provided was grammatically incorrect since cortas means to cut and Mrs. is used to introduce a married woman which should have been mes which means month.
Hope this helps! :3
1. I live
2. You live
3. He lives
4. She lives
5. You live (formal)
6. We live
7. y'all live
8. they live
9. they live
10. the woman lives
11. the grandma lives
12. Paco and Ana live
13. i can't see
14. My family and I live
15. The man lives