Go to nearest American embassy and they will help you.
Yes, US citizens need a visa to visit Argentina.
Yes, US citizens need a visa to visit Kazakhstan.
Yes, a Russian citizen can visit the US by obtaining a visa or participating in the Visa Waiver Program.
Yes, someone from Mexico can visit the US with a valid visa or through the Visa Waiver Program.
Yes, someone from Venezuela can visit the US with a valid visa or through the Visa Waiver Program.
Yes, US citizens need a visa to visit Saudi Arabia.
Yes, US citizens need a visa to visit South Africa.
If you are just going to visit him in the US, all you need is a visit visa (tourist visa) but if you are planning on making your home permanently there with him, he needs to apply for a K-3 spousal visa for you.
Yes, US citizens do not need a visa to visit Ireland for stays of up to 90 days.
Yes, US citizens need a visa to visit Malaysia for tourism or business purposes.
No you can get visa only once. Till your visa is valid you can visit multiple times
do danish citizens need a visa to visit Saipan Nothern Marianas