How do I write calligraphy works for my in-laws and sign them?

In fact, calligraphy works written for in-laws can also be called brothers, without writing anything like "in-laws", which is tacky. Just write "XX Jiao Zheng" or "Brother XX Zheng wrist" or "Letter from Mr. XX" and so on. You can also write a signature like writing a book for a friend, instead of writing it for your in-laws.