How can get Finnish visa?

The visa is a sticker that has been put in your passport. The number is, I think, the number that's printed vertically on the right. The only other numbers on the visa are the two lines along the...

Difficult - the H4 holder would have to be needed and benefit the US economy in his/her own right.

It depends on the laws of the country where you live. In most countries, they require background check in order to issue a visa no matter what the purpose is.

Finnish (the language) = "suomi" or "suomen kieli" A Finnish person= "suomalainen"

You are Finnish: "Sinä olet suomalainen." I am Finnish: "Minä olen suomalainen." Suomalainen is spelt with a lower case s.