He said that people had to obey their countries' laws.
2-he said,''I must tell you about dream I had last night''
He said that he had to tell him/them about the dream he had had the previous night.
3-he said,''we must have a party to celebrate this''
He said that they had to have/should have a party to celebrate that.
4-he said,''I have just received a message''
He said that he had just received a message.
5-he said,''you need to wait''
He said that I needed to wait.
6-he said,''when I was young I couldn't interrupt my parents''
He said that when he had been young he hadn't been allowed to interrupt his parents.
7-I said,''could you stand on your head'
I asked/wanted to know if/whether he/she could stand on his/her head.
8-She said,''if I had some flour I could make a cake''
She said if she had some flour she could make a cake.
9-She said,''if I could drive I would take you there myself''
She said if she were able to drive/could drive she would take me/him/them there herself.
10-I am going out tonight but I will be in by nine he said.
He said that he was going out that night but that he would be in by nine.
11-I am working in restaurant but I don't care he said.
He said that he was working in a restaurant but that he didn't care.
12-I can't live on my basic salary he said.
He said that he couldn't live on his basic salary.
13-We are waiting for school bus said children.
The children said that they were waiting for the school bus.
14-I have made a terrible mistake said John.
John said that ha had made a terrible mistake
15-You have made terrible mistakes I said.
I said that he/she/they had made terrible mistakes.
16-We have been here for tow and half years he said.
He said that they had been there for two and a half years.
17-We will wait for you if you are late they said.
They said that they would wait for him if he was late.
18-I hope you will all get what you want I said.
I said that I hoped they would all get what they wanted.
hopefully,I didn't miss any spelling mistakes.