If you have the new Turkish chip ID card and a phone with NFC, this is the quickest way to prove who you are on e-Devlet. When you hold the card against the back of the phone, the app reads the chip and marks the phone number on your account as "verified with ID". That verification is required before you can turn on two-step login, which keeps your account safe even if someone gets hold of your password. It is also one of the ways to clear a SIM block after you switch to a new SIM card.
This guide walks you through scanning the card in the e-Devlet Kapısı mobile app and then switching on two-step login. The steps come from e-Devlet's own help pages and user guides. According to those guides, you sign in to the app with your e-Devlet password or mobile signature; the card is scanned to confirm your identity, not used as a sign-in method. The app's screens are in Turkish, so the button names are given in Turkish with an English explanation.