Depending on why you are coming to Turkey and how long you are staying, you may need a visa and other permits. No matter where you are from or why you come to Turkey, you will need a valid passport from your country of origin.
Your passport should also have at least 90 days validity remaining. Even if your passport is within 6 months of its expiration date, consider renewing it before your trip or move to Turkey.
Whether or not you need a Turkish visa will depend on your country of origin and the length of and reasons for your trip. Many countries have signed Visa Exemption Agreements that allow their citizens to visit Turkey for up to 3 months without a visa.
Certain nationalities that are not visa exempt must obtain an online E-visa (in effect since 2014) before point of entry into Turkey.
For a list of these countries and their permitted lengths of stay, check with the Turkish Ministry of Foreign Affairs .
The Ministry also lists fee amounts on its website.