Every country has its own set of rules regarding the entry of visitors from different nationalities. For some countries, it is a requirement that passports have to be valid for a minimum period before they will issue a visa. Some countries grant visas upon your arrival.
Before you fly, do contact the embassy or consulate office of the country you will be travelling to for the latest information on visas or entry requirements.
IATA Travel Centre - Passport, Visa & Health travel document requirements
For most countries, the airport tax has been included in the final total and is to be paid upon booking unless stated otherwise that the tax is to be paid at the respective airport before departure. All refund of airport tax will be subject to a processing fee.
IATA Travel Centre - Customs, Currency & Airport Tax regulations