iOS is not the best OS for privacy. Only an open source and privacy-focused OS can provide the best privacy option and should be trusted. That said, many people love iOS and I'd like to share with you some privacy tools, apps and settings that can help iOS users.
1. Face ID and Touch ID — The odds of an individual spoofing FaceID or Touch ID are quite low. They are a pretty secure and convenient way to lock/unlock your device but may be vulnerable to targeted attacks, so the choice of whether or not to activate it essentially depends on your threat model.
2. Passcode — Use a six digits or alphanumeric passcode to lock/unlock your device. A four digits passcode can be cracked pretty easily and won't protect your device for long. Set the option to require passcode immediately. Enable the “erase data” option (only if you know what you're doing).
3. Lockscreen – Make sure notifications as well as Siri are not publicly accessible on your lockscreen. Also set your screen to auto-lock, and do not set it to leave the screen turned on.
4. Apple ID – Enable two-factor authentification.
5. iCloud – Disable everything related to iCloud.
6. Wi-Fi – Block your phone from auto-joining hotspots and wireless networks.
7. Bluetooth – Always disable it unless needed.
8. SIM – Set a custom PIN for your SIM card (not 0000).
9. Updates – Enable automatic updates (to get security updates as soon as they're released).
10. AirPlay & AirDrop – Disable AirPlay, Handoff and AirDrop.
11. Siri – Disable everything from Siri and Search.
12. Location services – Disable for everything except navigation apps, and set those to “While Using”. Disable all system services.
13. Privacy – Disable everything: app tracking, personalized ads, all analytics & improvements options (Siri, dictation, iCloud analytics…). Review all the other settings and make sure apps only have access to the settings they actually need, and nothing more.
When you install a new app, go to this app's permissions in your settings and make sure everything is disable unless needed. I encourage you to remove as many unused or infrequenly-used apps from your phone as possible.
1. Web browser – You can use a second web browser like DuckDuckGo Privacy Browser, Firefox Focus, Brave or Snowhaze. Change the default search engine to something like DuckDuckGo, Startpage or Mojeek. If you use Safari, disable cross-site tracking in the settings. For using Tor, use the unofficial Onion Browser.
2. Navigation – Apple Plan is pretty good, but you can use OsmAnd, Magic Earth or Organic Maps if you're looking for something more privacy-friendly.
3. Messaging – Use Signal (or Element) instead of iMessages.
4. Email – Use Tutanota, ProtonMail, or another secure mail provider.
5. Firewall & content blocker – Use DNSCloak, AdGuard or Blokada to block ads and trackers, and prevent your apps from contacting unnecessary servers.
6. Password manager – Use a password manager like Bitwarden to securely generate and manage all your passwords.