For most countries you do not need a special VISA to enter Argentina.
Nationals of the following countries do not require visas to visit Argentina for a period not exceeding 90 days or for transit:
United States of America (Reciprocity Fee), Andorra, Armenia, Australia (Reciprocity Fee), Austria, Barbados, Belgium, Bolivia, Brazil, Bulgaria, Canada (Reciprocity Fee), Chile, Colombia, Costa Rica, Croatia, Cyprus, Czech Republic, Denmark, Ecuador, El Salvador, Estonia, Finland, France, Germany, Greece, Guatemala, Guyana, Haiti, Holy See, Honduras, Hong Kong S.A.R., Hungary, Iceland, Ireland, Israel, Italy, Japan, Kazajastan, Korea, Latvia, Liechtenstein, Lithuania, Luxembourg, Macedonia, Malta, Mexico, Monaco, Montenegro, the Netherlands, New Zealand, Nicaragua, Norway, Panama, Paraguay, Peru, Poland, Portugal, Romania, Russian Federation, Saint Kitts and Nevis, Saint Lucia, San Marino, Saint Vincent and the Grenadines, Serbia, Singapore, Slovakia, Slovenia, South Africa, Spain, Sweden, Switzerland, Thailand, Trinidad and Tobago, Turkey, Suriname, Ucrania and United Kingdom of Great Britain and Northern Ireland and Uruguay.
Venezuela (up to 60 days).
Grenada, Hong Kong (With British Passport B.N.O, Jamaica and Malaysia (up to 30 days).
PLEASE NOTE: Citizens from the US, Canada and Australia must pay a "reciprocity fee" on their arrival to Argentina. This fee is NOT a visa; for USA arrivals it is US$131; Canada: US$75; and Australia: US$100. These fees are similar to the amounts that Argentinean citizens pay for visa applications to visit the US, Australia and Canada and may be subject to change. For US citizens, payment of the BA Airport Entry Fee allows unlimited entries to Argentina for a period of 10 years.
You have to go through the immigration office website
Here you will find the complete instructions here.