The e-Visa is an alternative to visas issued at Turkish missions and at the ports of entry.
Applicants obtain their visas electronically after entering required information and making payments by a credit or debit card (Mastercard, Visa or UnionPay) on the official website ... www.evisa.gov.tr/en/
The link to download your e-Visa is given on the final step of the procees on the above website and the same link to download your e-Visa will also be emailed to you. Passport control officers at ports of entry can verify your e-Visa on their system. However, you are advised to keep your e-Visa with you either as a soft copy (tablet PC, smart phone, etc.) or as a hard copy in case of any failure on their system.
As in the case of other visas, respective Turkish officials at the ports of entry reserves the right to deny entry into Turkey to a holder of an e-Visa without any explanation.