# Call Blocking & Identification on iPhone: How It Works URL: https://byshahid.com/blog/call-blocking-and-identification-iphone/ App: Secret Codes: IMEI & Carrier (https://apps.apple.com/us/app/secret-codes-imei-carrier/id6807154322) Author: Muhammad Shahid Updated: 2026-11-04 > Control which apps can label or block incoming calls. Third-party apps — including the carrier apps from Verizon, AT&T and T-Mobile — can register a call-identification extension with iOS. This screen shows which ones are active and lets you reorder or disable them. If unwanted calls stopped being labelled, this is the first place to check. - **What it does:** Control which apps can label or block incoming calls. - **Published for:** any iPhone, Verizon, AT&T, T-Mobile and UScellular - **Type:** iOS setting Control which apps can label or block incoming calls. This page explains what it does, how to use it on an iPhone and which carriers it applies to. I build **Secret Codes: IMEI & Carrier**, a free iPhone app with 317 checked codes and guides, including this one. If you would rather tap than memorise, [get Secret Codes on the App Store](https://apps.apple.com/us/app/secret-codes-imei-carrier/id6807154322). ## What is Call Blocking & Identification? Third-party apps — including the carrier apps from Verizon, AT&T and T-Mobile — can register a call-identification extension with iOS. This screen shows which ones are active and lets you reorder or disable them. If unwanted calls stopped being labelled, this is the first place to check. ## How do I do it? - Open the Settings app. - Tap Apps, then Phone (or tap Phone directly on earlier versions of iOS). - Tap Call Blocking & Identification. - Turn individual apps on or off, and drag to set their priority. ## Which carriers does this apply to? | Published for | any iPhone, Verizon, AT&T, T-Mobile and UScellular | | Type | iOS setting | | Good to know | Requires a call-blocking app to be installed. Each carrier ships its own. | _Screenshot: The Secret Codes detail screen shows the steps, the carriers and an Open in Phone button._ ## Related caller id codes - [Manage Blocked Numbers](/blog/manage-blocked-numbers-iphone/) - [Silence Unknown Callers](/blog/silence-unknown-callers-iphone/) - [Show My Caller ID Switch](/blog/hide-caller-id-iphone/) - [#787#: Check Scam Block Status (T-Mobile)](/blog/check-scam-block-status-t-mobile-hash-787-iphone/) - [#632#: Turn Off Scam Block (T-Mobile)](/blog/turn-off-scam-block-t-mobile-hash-632-iphone/) - [#662#: Turn On Scam Block (T-Mobile)](/blog/turn-on-scam-block-t-mobile-hash-662-iphone/) See all [caller id codes](/blog/iphone-codes/caller-id/) or [every category of iPhone codes](/blog/iphone-codes/). ## How Secret Codes helps Secret Codes keeps this and every other entry a search away. Pick your carrier once and each entry says whether it is published for your line. You can save favourites, add a private note, and record whether a code worked on your line. This entry is part of Secret Codes Pro. **Secret Codes: IMEI & Carrier** is free on the App Store: https://apps.apple.com/us/app/secret-codes-imei-carrier/id6807154322 ## FAQ ### What is Call Blocking & Identification on iPhone? Control which apps can label or block incoming calls. Third-party apps — including the carrier apps from Verizon, AT&T and T-Mobile — can register a call-identification extension with iOS. This screen shows which ones are active and lets you reorder or disable them. ### What else should I know about Call Blocking & Identification? If unwanted calls stopped being labelled, this is the first place to check. ### What are the steps for Call Blocking & Identification? 1. Open the Settings app. 2. Tap Apps, then Phone (or tap Phone directly on earlier versions of iOS). 3. Tap Call Blocking & Identification. 4. Turn individual apps on or off, and drag to set their priority. ### Where do I find Call Blocking & Identification? In the Settings app on your iPhone. ### Is there a dial code for Call Blocking & Identification? No. On iPhone this is not a dial code, so you use the steps on this page instead. ### Which carriers does Call Blocking & Identification work on? It is published for any iPhone, Verizon, AT&T, T-Mobile and UScellular. Requires a call-blocking app to be installed. Each carrier ships its own. ### Does Call Blocking & Identification work on Android phones too? These steps are for iPhone. Android phones have their own menus. ### Will Call Blocking & Identification work outside the US? The iPhone steps stay the same, although some features depend on your carrier and region. ### What if Call Blocking & Identification does not work on my iPhone? Check that it applies to your carrier first, because carriers decide which services they offer and can change them. If it should apply to your line, contact your carrier. ### What is related to Call Blocking & Identification? Manage Blocked Numbers. Review and edit everyone you have blocked. ### What else is in this category? Silence Unknown Callers. Send calls from numbers you don't know straight to voicemail. ### Can I find Call Blocking & Identification in an app? Yes. Secret Codes, a free iPhone app, includes it with its steps and carrier details, as part of Secret Codes Pro. ## Sources - [3GPP TS 22.030: Man-Machine Interface of the phone](https://www.3gpp.org/dynareport/22030.htm) - [Apple Support: iPhone User Guide](https://support.apple.com/guide/iphone/welcome/ios)