Compulsory military service or often abbreviated as a military officer is an obligation for a young citizen, especially men, usually between 18-27 years old to carry weapons and become members of the army and take military education to improve one's resilience and discipline. Wamils ​​are usually held in order to improve discipline, toughness, courage and independence of a person and are usually held mandatory for male men. Those who have to be army officers are usually male citizens. Women are usually not required by the army, but there are also countries that require it, such as in Israel, North Korea and Suriname. Students also usually do not need to join the army. Some countries also provide alternative national tasks (alternative services) for citizens who cannot enter the military for certain reasons such as health, political reasons, or cultural and religious reasons.

At present, the army is controversial, because of the refusal, especially to serve a government that is not favored by some parties, unpopular war (Vietnam War), and classified as violations of individual rights. People who enter the army can avoid it, sometimes leaving their country.