what is the correct format of a notice which is to be placed in a newspaper...thanking everyone for their support, hospital care etc

The family of X wishes to express its thank to X, Y and Z. What you want to say after that is your choice, how specific or non-specific you want to be.

I don't know if anyone reads those notices, anyway.

My late husband was totally against those "anniversary of your death" notices - you know, "Mom, I'll always love you" sort of stuff. He said he had no plans of getting the newspaper wherever he was after this life.