Can an immigrant who came into the usa with a visa go into canada as a visitor?

If you are a green card holder, you don't need visitor's visa to go to Canada and Mexico.. just your passport and green card.

If you are a greencard holder, you don't need visitor's visa to go to Canada and Mexico.. just your passport and greencard.

What if this person doesn't have a green card?

Then what is his/her legal status in US? What kind of visa?

If you have legal status here in US, such as work visa or student visa, you can obtain visitor's visa to go to Canada, and return to US.

If you have US visitor's visa, single or multiple entry, you can obtain visitor's visa to go to Canada BUT you won't be allowed to return to US.

Yup, it just depends what kind of visa you have, if you have a multiple entry visa then you can return to the US, if it's single entry you cannot.

Best to check with USCIS before you leave the country.

At present, if you visit US with multiple entry visitor's visa, if you go to Canada, US immigration won't let you return to US. This is to prevent people who want to get new I-94 in order to spend another 5-6 months in US for the second time.