This article explains how to disable the passcode on your iPhone.
Steps
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Step 1. Open the "Settings" application
The icon looks like gray gears and is on the Home screen.
The "Settings" application may be located in a folder on the Home screen called "Utilities"
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Step 2. Scroll down and select Touch ID & Passcode
This item is located in the third section of the settings menu.
If your phone does not have a Touch ID, this menu option will be called Passcode
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Step 3. Enter the code
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Step 4. Click on Disable code
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Step 5. Press Disable again to confirm the operation
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Step 6. Enter the code
This will disable it. You will no longer have to enter any passwords to unlock your phone.