We’ll give you here many tips, and recommend great tweaks to secure your iPhone.
Protect from lost / thief
Define a strong password
Don’t be satisfied with a 4-digit code, that could be broken in a few minutes. Define password at least 7 characters long.
Enable screen lock settings
Enable the screen lock after a few minutes inactivity.
Limit information displayed on the screen lock
Don’t popup messages on lock screen through the lock screen privacy options.
Turn on USB Restricted Mode
Prevent unauthorized connection of USB accessories to the iOS devices.
Disable Siri voice control
Disable ‘Siri’ trusted voice, especially on lock screen.
Receive AirDrop Only From Contacts
Receiving files from unknown contacts is not recommended as you never know what kind of files you will receive from strangers.
Back up your data
Prefer app which back up or synchronise data on the cloud, so if you lose your phone, or need to erase it remotely, you’ll still have your data (especially your passwords, and your pictures).
Enable ‘find my mobile’
Enable “Find my mobile” and make sure you can erase your mobile remotely if needed.
Protect from trackers
Disable location services
Unless you are using it, disable location services.
Disable personalised advertising
Don’t serve Google all your personal information on a platter.
Don’t share any data with developers.
Turn off automatic sync to iCloud
Almost all celeb pics leaked on the net because of this function. Manually sync the pics you select.
Review and revoke permissions of apps
When not absolutely needed, don’t authorise apps to access your pictures, your location, etc…
Use progressive Web apps instead of apps
Native apps can just help themselves in your phone, which is not the case when you use a browser to access their content (ex newspapers, twitter…).
Use a VPN to hide your IP address
Use a browser respectful of you privacy
Use a respectful search engine
Search the web with an engine that doesn’t log all you behaviour. Replace Google Search by DuckDuckGo (free).
Use a secure encrypted mailbox
Use secure encrypted messenger
Use a secure encrypted app to chat, like Signal (free)
Protect from hackers
Don’t jailbreak your system
Don’t jailbreak your system. And only install apps from official stores like Apple Store. Make sure automatic download and install are deactivated in the setup.
Discard automatic WiFi connections
This small effort will avoid you to connect on a fake wireless network established by a cybercriminal with the same name as a trusted public hotspot.
Update the OS and the apps
Enable auto updates for your operating system. These updates often include critical patches and protections against security threats. Make sure your apps also auto-update to mitigate vulnerabilities.
Use a password manager
Disable Smart Lock for Passwords and Auto Sign-in. And use a vault like Bitwarden (free) to generate and remember complex and different password for each account you have. It will also synchronise you passwords on all you devices.
Activate TOTP everywhere
Activate two factor authentication (2FA) through TOTP, and use an authenticator app like Authy (free).
Good to know
No need of antivirus
Unlike Android, and because of how iOS is structured and the permissions Apple lets apps have, you don’t need to worry about viruses on your iPhone.