To Write In A Wedding Card What Should I Write On My English Teachers Wedding Card?

What should i write on my english teachers wedding card? - to write in a wedding card

I was invited to my wedding because I am very friendly, English teacher of his son. But Im not what they write on your card. I do not know what kind marry shes so im not sure whether it should be sent to her, or just two.

Any idea what to write?

Thank you in advance.