Join Date: Nov 2018
Location: Istanbul, Turkey
Programs: TK Elite Plus,BAEC GGL,ITA Executive, AFKL Gold,QR Gold,HH Diamond,Bonvoy Gold,ALL Gold
Posts: 14,186
You should be able to see the e-ticket numbers when you log in to MMB on turkishairlines.com at the passengers tab when you scroll down.
If you bought your ticket from a TA or OTA you would need to contact them for the e-ticket number.