Locked iPhones hide the decline button, but side buttons reject calls

An iPhone shows different incoming-call controls depending on whether it is locked: the locked screen uses “slide to answer”, while an unlocked phone offers separate answer and decline options. This is the default behaviour, though users can still reject or silence calls with the hardware buttons.

Pressing the side button twice declines a call and sends it to voicemail; either volume button silences the ring. A Message option lets callers receive a prepared or custom text explaining why the call cannot be answered, and those replies can be edited in Settings. The article also notes that the FTC received more than 2.6 million Do Not Call complaints in fiscal year 2025, and that iOS 26 can screen unknown callers by asking why they are calling or sending them to voicemail.