I just finished my Turkey eVisa application and the document requirements were more detailed than I thought. Right at the start, I checked the Documents Requirements for Turkey Visa page and it cleared up everything for me. Your passport bio page needs a clear scan with no glare, and it must be valid for six months from arrival. Depending on your nationality, you also have to enter details from a valid residence permit or sticker visa issued by the Schengen area, Ireland, the USA, or the UK. For transit visas, keep your flight reservation ready too. That page really saved me from guessing and potentially messing up my application.