Please please check my grammar and my english thank you.

Hi Helene, how are you? I’m very happy that you are coming to the U.S. for a visit. I will just let you know what you should or should not do. You need to know, because of security, that you must not put any liquid soap, shampoo or a knife in your carry-on luggage. Also when you get to the U.S. makes sure that your passport and invitation paper is in your hand because, before you enter the US imigration will ask you for them. Another thing is in the U.S., we have four seasons, one of which is summer. Summer is very the hot season so you should bring light cloth like shorts, t shirts and dresses. I suggest you to stay in Washington D.C. because D.C. has a lot of things you can see. You must see the White House, monument, (which one? The Washington Monument? needs a capital letter as it is proper noun) Capitol Hill and the/some museums. I hope you like it and enjoy it. Good luck