This wikiHow teaches you how to allow installation of apps from outside the Apple App Store on your iPhone.
Step
Method 1 of 2: Installing Untrusted Apps
Step 1. Download and install the custom app
This application is made by the developer for the company's internal use. For example, you may need to install a customer management application, or an application to download data from the Web.
Step 2. Open the app
You'll see an "Untrusted Enterprise Developer" warning.
Apps you download from the App Store will get trusted status automatically
Step 3. Tap Cancel
Method 2 of 2: Trusting Special Apps
Step 1. Tap the gray cog icon (⚙️) on the home screen of the phone to open the Settings app
Step 2. Tap on General option
This option has a gray cog icon (⚙️) in one of the sections above the menu.
Step 3. Tap Profiles
This menu may have labels Profiles & Device Management.
This menu won't appear on your iPhone until you install and try to open an untrusted app
Step 4. Tap on the name of the app developer in the "Enterprise App" section
Step 5. Tap Trust [Name of Developer] near the top of the screen
Step 6. Tap Trust to allow iPhone to run your installed apps
In addition, applications from the same developer will also be automatically trusted.
