The reason why some iPhone calls don't have a decline option, and others do
Your iPhone's incoming call screen isn't as mysterious as it seems.
When your iPhone is locked, incoming calls display the slide to answer control. When your iPhone is unlocked, you get the option to answer or decline the call.
Depending on your Incoming Calls setting, Accept and Decline buttons appear in a compact banner or across the entire screen, but both options remain. This is simply how the iPhone operates by default, right out of the box, though adjustments can be made via Settings.
You don't need an on-screen button to decline or silence a call, however. You can press the side button twice quickly to decline and send the caller straight to voicemail. Or, you can press either volume button to silence the ring without declining the call.
How to respond to an iPhone call without answering it
Fortunately, rejecting a phone call doesn't have to come off as rude, because you can let the caller know why you rejected it. An iPhone's incoming call interface includes a Message option that lets you send a text instead of answering using prepared or custom options.
If the incoming call pops up as a banner while you're busy, tap the banner to reveal more options, then select Message. Go with a prepared reply or quickly fire off a text by choosing Custom to explain why they're being sent straight to voicemail.
You can also change the prepared replies well in advance. Open Settings, navigate to Apps, then Phone, and select Respond with Text to edit responses according to your preferences.
How to reject unwanted calls on an iPhone
To block persistent unwanted numbers, find the number you just rejected in Recents, tap it, scroll to the bottom of the screen, select Block Caller and confirm.
You can use a broader setting to screen unknown callers as well by going to Settings, Apps, Phone, and Screen Unknown Callers to select your preferred screening behavior.
Choosing to silence every unknown call means they go straight to voicemail without ringing, though convenience always comes with potential caveats regarding missed important contacts.
