You can start with this website http://nigeria.usembassy.gov/ A letter of invitation is usually advised. They may also need to show strong ties to their country, such as family, a job, home, a bank account.
Quick Answer. Over one billion Muslims live in Asia, which makes it the continent with the highest Muslim population. Indonesia is the country with the largest Muslim population, with 209 million people. Continue Reading.
By far, the largest populations of Muslims live in Southeast Asia (more than 60%), while the countries of the Middle East and North Africa make up only 20% of the total. One-fifth of the world's Muslims live as minorities in non-Muslim countries, with the largest of these populations in India, China, and Russia.