I would like to know how we should we pray wajib namaz in masjid e kufa masjid sehla and imam e Hussain (a.s) shrine?
Do we pray qasar or full namaz?

You have a choice between full or qasr. Full is better.
As for Imam Hussain shrine, you only have a choice if it’s 5 arms length from the actual grave. Otherwise it’s qasr