We can't complete Himachal in 7days. But still, you can cover some of them..Like Kasol, Tosh, Manali, Simla, Kasuili, Spiti Valley, Khajjiar, Mcleodganj, Dalhousie, Dharmshala etc.
This tour depends on your budget and which portion you want to go.
7 days is too less to visit Himachal or any other state for that matter. On the start on Himachal you have Kasauli, Solan, Chail , Shimla, Kufri, Theog, Narkand. This is not even 30% of himachal and it would take 10 days including travelling and exploring places