I have a question what the difference between ( have had ), (had had).

"Have had" is present perfect tense. "Had had" is pad perfect time. Ex...I have had my breakfast just now. I had had my bicycle before I bought bike.

have had: present perfect tense ex: I hv had dinner मैं खाना खा चुका हूँ। had had: past perfect. tense ex: when Ram reached I had had dinner. जब राम पहुंचा मैं खाना खा चुका था।