The newest iPhones and iPads contian a chip that submits your location to Apple every time you switch off your phone, even if you have location services switched off! And it will pinpoint your whereabouts even if you are using a VPN or have airplane mode on!
So let's address that first. You do have some options to make iOS fairly secure, but bear in mind not super secure/private!
I guess the start point has to be about choices. Is it better to give your data to Apple (which claims to be private by design and not an advertising company) or to Google (which uses your data 100% for advertising)? This is your very own choice, so go ahead, eyes wide open!
Let's now move on to the things you can and should do if you have an iOS device.
After you have done this go to
Location services →
System Services and switch everything off,
except the last point which says Status Bar Icon. This will ensure you
see if Apple or anyone else is still using the location services to
pinpoint you. Now, jump back one step and switch Location Services off!
Next, find advertising (still on the Privacy Screen), find
Personalised Ads and make sure it's off.
Now find Calendar on the Settings Page and switch off Location Suggestions.
Find Messages on the Setting Page
Keep Messages and chose 30 days
Find Safari on the Settings Page
Search Engine → DuckDuckGo
Search Engine Suggestions (Off)
Safari Suggestions (Off)
Block Pop-Ups (On)
Downloads → on my iPad/iPhone
Prevent Cross-Site Tracking (On)
Siri & Search (on the settings page)
Listen for "Hey Siri" → Off
Press Top Button for Siri → Off (if you use Siri, leave it on)
On this page you'll see all your apps (choose carefully what Siri should be allowed to use, or switch all off)
In General (Settings Page) find Background App Refresh
Choose here what you actually need and improve battery life that way. It should go without saying that we recommend using a strong one with at least 6 digits Pin Protection, or when you have a newer iPhone you need to unlock with your face!
Sign out of iCloud, you can download apps from the App Store without iCloud!
Be careful when you have 2FA on, as you need either SMS or a second iOS device or Mac to allow you to go back in! If you like to stay signed in, switch off Find My and chose in iCloud what you are willing to have in the cloud. Make sure iMessage and FaceTime is not backed up into the cloud. I also highly recommend switching Photo off in iCloud! As nice as this sounds, we’ve seen iCloud photo leaks in the past but worse than that, you allow Apple to scan your pictures!
As great as this sounds, we do not know how deep this rabbit hole goes. The main point here is they scan your pictures and they are also there for people to see if they find out how to hack iCloud! Remember, this has happened multiple times in the past!
Make sure you also do:
Password & Security → Two-Factor Authentication: On
If you don't use Wi-Fi disable it
Ask to Join Networks: Off
Auto-Join Hotspot: Off
If you don't use any connected devices, switch it Off
Disable Cellular Data for any apps you don't need access to
Show Previews: Never
Screen Sharing: Notifications Off
Siri Suggestions → Allow Notifications: Off
Software Update → Automatic Updates: On
AirPlay & Handoff: Disable all
Background App Refresh: Switch all Off that aren't needed
Display & Brightness:
Raise to Wake: Off
Tracking: Allow Apps to Request to Track: Off
Analytics & Improvements: Off
Apple Advertising: Personalised Ads: Off
Content & Privacy Restrictions: Enable.
Then put all Privacy settings to: Don't Allow.
Allowed Apps: Disable all (except what you really use)
Allowed Changes: Set all to Don't Allow.
App Updates: On
Personalized Recommendations: Clear App Usage Data
Wall & Apple Pay:
Turn everything off. Also use a Password Manager, not the built-in one Apple provides.
Game Center: Disable
I recommend using AdGuard on iOS.