In your settings app, click on your profile

Enter and verify your new password or passphrase, then hit change to complete the process

Next, you'll see a screen of devices you haven't signed into for more than 90 days. You should click Sign Out of Devices for any device you no longer use

Now, follow the steps Apple lays out to add your security keys. NOTE: Apple requires you to add two security keys to complete the process

Go back to the Password & Security page. Scroll down and click Account Recovery

Here, you will see your recovery key. Write it down, or print a copy, and store it in a safe space. Then click continue

Enter the recovery key and click next to complete the process

Back on the main Settings screen, scroll down and click Privacy & Security

On this screen, you can toggle off using all location services by clicking here. You can also adjust how each app uses location settings on this screen as well.

For example, here you can see whether the camera app has access to location services. You can choose whether an app has no access to location, whether they can access location while they use it, or to ask next time you use the app.

You can also determine whether an app can access your exact location. For some apps, such as ridesharing apps, it's helpful to have precise location on for drivers to know exactly where to pick you up.

At the bottom of the Location Services page, scroll down and click System Services

Here, you can adjust whether you want to receive location-based alerts and services. Next, let's click on Significant Locations

Here, you can choose whether you want your device and iCloud to learn places it deems significant to you to provide location-based information in Maps, Calendar, Photos and more. If you have this service on and want to erase all the locations your device has collected, click Clear History at the bottom of the screen 

Back on the System Services page, it's recommended that you turn off the iPhone analytics and Routing and Traffic features if you are more privacy conscious

Back on the Privacy & Security page, click Tracking

Here, you can choose which apps are allowed to track your activity across other companies' apps and websites. If you don't want any app to track your activity, click here

Adjusting Analytics & Improvements Settings

Back on the Privacy & Security page, click Analytics & Improvements

Here, you can choose whether you want to share your iPhone or iCloud analytics data and your safety data

Back on the Privacy & Security page, scroll down and click Apple Advertising

Click here if you do not want to receive targeted advertisements

Back on the Privacy & Security page, click App Privacy Report

Here, you can see how often apps access your data and their network activity over the past seven days. This gives you a more complete overview of how apps treat your data and make an educated decision whether to keep uninstall an app if it is accessing too much of your data.

Back on the Privacy & Security page, click Lockdown Mode

Here, you can turn on Lockdown Mode. Apple considers this to be a last resort of sorts. If you believe you have been personally targeted in a cyberattack, you can turn on lockdown mode. When you do, your device will not function as normal. You will not be able to use most of your apps and messages and FaceTime functionality will be severely limited. 

On the main Settings screen, scroll down and click Mail

Click here if you want to hide your IP address from email senders whenever a message is opened

On the main Settings screen, scroll down and click Safari

Scroll down until you see these features. Here, make sure “prevent cross-site tracking” is turned on. This prevents third parties from tracking your activity across multiple websites. You can also hide your IP address from trackers by clicking here

On this screen, make sure From Trackers is checked

Stolen Device Protection adds a layer of security when your iPhone is away from familiar locations, such as home or work, and helps protect your accounts and personal information in case your iPhone is ever stolen.

NOTE: This feature will not work if Significant Locations is turned OFF.

Enter your passcode

NOTE: Even if someone knows your passcode , if you are away from home, additional biometric identification will be needed (touch ID/Face ID) to change settings or access stored passwords.

If your personal safety is at risk, you can use Safety Check on iPhone to quickly stop sharing your information, or to review and update sharing with individual people and apps.

Here, you'll have the choice between Emergency Reset and Manage Sharing & Access. First, click Emergency Reset

Here, you will see the four steps of the Emergency Reset. You'll be able to stop sharing data with people and revoke access from all apps on your phone, add or remove emergency contacts, trusted devices and phone numbers and change your Apple account passwords and your iPhone passcodes. Click this button.

If you want to reset all of your settings for sharing information with people and apps, click reset. If you want to do it for certain apps and people, click Manage Sharing & Access. Repeat for the other three steps as well.

Back on the Safety Check page, let's click Manage Sharing & Access

On this screen, you can see who you are sharing information with and make the decision whether you want to continue sharing with that person. Once you are done, click continue.

You are done with step 1. Click continue.

Here, you can adjust which apps have access to your information and decide whether you want them to continue having access to your data. You can also click Select All & Stop Access if you want to stop all apps at once.

Here, you can add an Emergency SOS contact. After you have done so, click continue.

Next, you'll be able to review any device connected to your Apple ID. Click continue

On this screen, you can see which devices are connected to your Apple ID. Choose which devices you no longer wish to have linked to your Apple ID and select Remove Selected Devices.

You can then choose to update your Apple ID password now by clicking the blue button, or choose to update it later in Settings to move onto the next screen.

On the next screen, you'll be given the same choice for updating your device passcode.

iOS Hardening Guide