visa is needed by nationals of most countries although they may be somewhat
strict in enforcing that you have a return/onward ticket and sufficient funds
for your stay.
Nationals from Afghanistan, Bangladesh, Indonesia, Iraq, Iran, Laos, North Korea, Libya, Mali, Pakistan, Palestine, Philippines, Sahrawi Republic, Somalia, Sri Lanka, Sudan, South Sudan, Syria, Taiwan, Viertnam and Yemen need a visa prior to arrival.
Everyone else either needs no visa or can buy a visa on arrival at the airport.
To apply email firstname.lastname@example.org.