Entering as a spouse of a citizen, Form I-130, Petition for Alien Relative.
My husband & I went thru this back in 98 and again in 2001 when our file had been sent to another office and no one told us, so we changed our address with the office we'd filed with and they requested our interview - but we never went (didn't know!) and so our application was considered abandoned and we had to reapply everything.
Do note, at that time, that the US has a requirement for sponsorship though, unlike in Canada where if it's spouse/children there is none. We ended up needing a co-sign sponsor with our first application and with our second my husband had the income to sponsor himself.
We are now in the process of filing to move back to Canada and from everything we understand he WILL lose his PR status here in the US.