Rabbi I have a a friend whose child is missing. In addition to tehilim(general purpose) is there a separate specific teffilah or bracha asking the KBH to bring their daughter back safe?

ב"ה Shalom, I am so sorry that I have not noticed your question. I did not realize it has been waiting in my box for a few days now. As I have said in a previous answer any Tehillim is appropriate. However, in times of trouble many have the custom to say chapters 20, 121, 130 and 142. You may want to divide the saying of the entire Tehillim among several people. There are also websites which you can enlist to get as many people as possible to join in saying Tehillim. Besorot tovot.