Passports should be valid at least six months longer than the expiry date of the requested visa. The term "official passports" covers diplomatic, service, special and official passports. Regardless of the visa regime applied towards the citizens of a country, the travel document holders of that country need to obtain visa from Turkish missions beforehand.
If you have a valid visa, you do not need a residence permit up to 90 days. On the other hand, foreigners who shall reside, work or study in Turkey, should register themselves at the nearest local police department upon their arrival in Turkey, regardless of the validity of their visa.
As of April 17, 2013, electronic visa (e-Visa) replaces “sticker visa” which was issued at the border crossings. Applicants just need to log on to www.evisa.gov.tr, provide the requested information, (after the application is approved) make online payment and download their e-Visa. Please note that e-visa is only valid when the purpose of travel is tourism or commerce. Other purposes, such as work and study, require regular visa given by Embassies or Consulates.