Explanation

 he said" Ahmed wrote a novel" 

change into the narration:  he said that Ahmed had written a novel"

In the first speech, there is a quotation – "  he said" Ahmed wrote a novel" ”

As it is quoted directly from someone’s speech "he said that Ahmed had written a novel"

In both ways, I am giving descriptions of a person, i.e. I am narrating something about a person.