The Ministry of Trade has recently been placing greater emphasis on registering websites that sell goods or services online with ETBİS (the Electronic Commerce Information System). If your hotel's website takes bookings or accepts payments directly, you may need to register. The process is straightforward and is done via e-Devlet (Türkiye's e-government portal) by an authorised company representative. After registering, you log in, click "Create Site" and enter your hotel website's details; the system then generates a QR code for you, which you must place in your site's footer.
ETBİS registration and QR code video (in Turkish) — for details see the Ministry's page