If you're concerned about your privacy and want to limit your dependence on Google, using an iPhone is a good idea but it's not enough. Here are the settings and applications that I recommend to protect your personal data.
Limit Application access to your personal data
Location service
To better understand the seriousness of the circulation of location data from millions of people to companies that no one knows, I advise you to read the following investigation from the New York Times: Twelve Million Phones, One Dataset, Zero Privacy. The problem is not only that some of your applications have frequent access to your location, but also that these applications also transmit your location to third-party services (advertisers and resellers of personal data) of whose existence you are completely unaware.
How to limit risks as much as possible? Go to "Settings", "Privacy" then "Location Services", this is where you will see the apps that have permission to access your location.
A good idea is to restrict these accesses as much as possible: “Never” should be your default choice. Here are the options:
Here it is interesting to note a new option introduced with iOS 13, “Ask next time”: you will be able to choose each time you launch the application whether you want to activate geolocation or not.
Other access to restrict for applications
While real-time location tracking is the most sensitive personal data, your iPhone apps also have access to other personal data. It is therefore recommended to take a look at each of these data to restrict certain applications, always via “Settings”, then “Confidentiality”. You might get surprises like how many apps have access to your contacts or your Bluetooth.
Enable limited ad tracking
Still in "Settings", then "Privacy", now go to "Advertising" to check "Limited advertising tracking". Unfortunately, this setting is not necessarily followed by application developers, but they have access to it and can therefore decide to no longer show you targeted advertising. You can also regularly reset the advertising identifier (equivalent to deleting cookies on your browser, and therefore starting from scratch with respect to advertisers).
Protect your web surfing
Since Apple does not allow other browsers to use their own rendering engine, there is no system of extensions that you could add to a browser, as you could, for example, with Firefox on Desktop or Android.
I therefore advise you to keep Safari, especially since it has done a lot lately to block ad trackers (via a mechanism called Intelligent Tracking Prevention, which has a spectacular effect on advertisers). You can go further by installing an adblocker, using private browsing and changing the default search engine.
Add an adblocker
Since Safari doesn't allow adding extensions, you may be wondering how to block ads. It turns out that since iOS 9, Apple has allowed "Content blockers", third-party applications that allow you to block a list of domains when browsing on Safari, which effectively allows you to block advertisements (only on Safari, not in applications). Here I recommend you to install the application Firefox Focus, which works remarkably well on my iPhone.
Firefox Focus contains a browser, useless if you use Safari (ironically, the Firefox Focus browser does not block ads), but it also contains a content blocker for Safari, very effective: as you can see above, it can block ads, but also statistics trackers (like Google Analytics) and social network trackers (like Facebook or Twitter).
To activate it, you need to go to “Settings”, then “Safari” and finally “Content blockers”.
Switch to private browsing
Not being in private browsing is of little benefit on mobile: when you are connected, you generally use an application and not Safari. Keeping your browser in private browsing mode automatically deletes cookies at the end of your session, and therefore prevents websites from tracking you from one session to the next.
Change your default search engine
On Safari, the default search engine is Google. If this one is still the best, most of the time you will have equally satisfactory results using DuckDuckGo, a search engine that respects the privacy of its users by not logging their queries. To select DuckDuckGo, go to "Settings", then "Safari" and finally "Search Engine".
Protect yourself when using an application
Apps are well placed to track you because they often have access to your iPhone's features: your advertising ID, and potentially other information such as your location, camera, Bluetooth access, etc.). What you probably don't know is that these applications can easily transmit this personal information to third parties (often advertising or audience measurement tools). How to block these third parties?
If content blockers only work on Safari, it is possible to find adblockers that will block advertisements displayed on applications. This requires specialized applications. The VPNs may also allow you to hide your IP address from your internet service provider and the sites you visit.
DNSCloak: the adblocker for applications
DNSCloak is a handy application that allows you to choose a DNS proxy provider. Quesako? The DNS is an essential service on the internet: it matches between IP address and domain name. When you type "google.fr" into your browser, a request is first made to a DNS server (usually that of your internet service provider) to find out the IP address of "google.fr" (here: 172.217.20.131). Since iOS 11, Apple allows the use of a DNS proxy, the proxy can provide several functionalities: request encryption, advertising request blocker, etc. On DNSCloak, I use adguard-dns, which allows me to remove advertisements.
ProtonVPN: to hide and secure your browsing
If you want to secure your browsing and hide your IP, you need a VPN. This intermediary is then the only one to know your IP, so you must choose it with the greatest caution. ProtonVPN is offered by the publisher of Protonmail, an encrypted email service based in Switzerland, developed by scientists at CERN and MIT, and having acquired an excellent reputation for defending privacy. The crucial point: ProtonVPN does not keep any logs of your traffic (and Swiss law does not require them to do so), so it is impossible for them to analyze your browsing afterwards. Note that you can also use ProtonVPN on your other devices (Mac, PC, etc.).
Protect your iPhone in case of theft
If your iPhone is stolen, it is important that your personal data is encrypted so that the thief cannot access it. To do this, go to “Settings”, “Touch ID and code”, and create your 6-digit code. Also, please activate the option that allows you to erase data from the iPhone after 10 attempts (which will protect your iPhone from a brute force attack). On the importance of encryption, read Tim Cook's letter, Apple CEO, on his refusal to compromise iPhone encryption during the case between Apple and the FBI.
Here you should see the message "Data protection is activated."
Protect your Apple account in case of password leak
This is a good practice, also valid for your other accounts (Google, Facebook, etc.): activate two-factor identification to protect access to your Apple account (your iCloud password alone will not be enough to access your account). To do this, go to “Settings”, then tap on your name, and finally “Password and security”.