Understand certain differences in Assistive Access on iPhone
Assistive Access apps have been redesigned for cognitive accessibility and include larger text and icons, more focused features, and customizable options. In addition, some features work differently in Assistive Access—this page explains certain important situations where you need to exit Assistive Access.
Contacting Emergency Services
You can place an emergency call from an iPhone in Assistive Access by triple-clicking the side button (on an iPhone with Face ID) or Home button (on other iPhone models), or by holding the Sleep/Wake button and one of the volume buttons (on any iPhone model), then tapping Emergency and dialing your local emergency number using the Emergency keypad. Alternatively, when you set up Assistive Access you can add the Calls app and allow calls to anyone. It’s recommended that you set up your Medical ID in the Health app so critical medical information is available to first responders. This information can be accessed without a passcode from the Emergency keypad. See the Apple Support article Set up your Medical ID in the Health app on your iPhone.
If Crash Detection is available and enabled on the iPhone, it will continue to work in Assistive Access.
Emergency SOS via satellite isn’t available in Assistive Access, but can be used on supported iPhone models when you exit Assistive Access.
All other automatic dialing to Emergency Services isn’t available in Assistive Access. To text Emergency Services (not available in all countries or regions), you must either exit Assistive Access or add the applicable emergency services number to the Contacts app and add it as an allowed contact to send messages to in Assistive Access.
App permissions
To minimize pop-ups while using iPhone, apps won’t ask for permission to access information such as location, photos, and contacts. Instead, you have the option to set access permissions for apps when you set up Assistive Access. To review or change an app’s permissions, you must exit Assistive Access and go to Settings 
> Accessibility > Assistive Access or Settings > Apps > [app name].
Software updates
You must exit Assistive Access and go to Settings in order to install new software updates, because there is no Settings app or notifications in Assistive Access that indicate whether an update is available.
Privacy and device information
Certain app privacy information, status icons, and symbols aren’t available in Assistive Access, including those that indicate network availability, Airplane Mode, Focus, or Bluetooth®, or when an app or website is using Location Services. You can exit Assistive Access to view this information.
Calls and messages
When you set up Calls for Assistive Access, you can choose to allow calls with anyone, all contacts in the Contacts app, or favorite contacts only. If you choose to allow calls to anyone, the person using Assistive Access can call any contact, as well as enter a phone number to make a phone call, and return calls from anyone who has called them. If you don’t allow calls with everyone, you must exit Assistive Access to make or receive calls from anyone who’s not an allowed contact.
When you set up Messages for Assistive Access, you can choose to allow messages with anyone, all contacts in the Contacts app, or favorite contacts only. If you choose to allow messages to anyone, the person using Assistive Access can send a message to any contact, and return messages from anyone who has messaged them. If you don’t allow messages with everyone, you must exit Assistive Access to send or receive messages from anyone who’s not an allowed contact. Even if you allow messages to anyone, you must exit Assistive Access to send a message to someone who’s not an allowed contact if they haven’t already sent you a message.