I went back and forwards to one company (though I was self-employed status mostly) during the entire time I was visiting and living in the Phils...around 15 years in all.
The letter can be quite simple, stating the basic facts, but company letter-headed of course, and signed by a director or head of HR.
Here off the top of my head.....
'To whom it may concern.
From (date) Mr........ of (husband's address) will be employed by this company as a ............
The position is full-time, and is considered permanent. He will be paid a gross annual salary of..........
Kindly address any queries to the undersigned.
.........................'
