The correct answer to this open question is the following.
Here is my letter.
Hi Mr. Kyle,
This is just a short letter to express my gratitude for the wonderful opportunity you gave me for having me facilitated the award of the scholarship to study at the National University in Mexico City.
Dear professor Kyle, it was a great experience I would never forget.
It has been a couple of months and I just arrived from this great experience.
You do not have how important was for me to know more about another and fantastic culture as the Mexican culture. I had the chance to make new friends, to know different teachers and styles of teaching.
These were months of learning not only the school subjects, but how people my age think, believe, and aspires in life.
This was a life-changing experience, and for that, I will always be in debt to you Mr. Kyle.
Again, thank you very much for your help and hope I can visit you soon.
Best regards,