Summary
You can turn off the Sleep Focus setting on your iPhone to prevent it from automatically going to sleep. To do this, open Control Center and tap Sleep.
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This setting will remain off until you turn it on again at any time.
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You can also control access to information on the iPhone Lock Screen by going to Settings > Face ID & Passcode (on an iPhone with Face ID) or Touch ID & Passcode (on an iPhone with a Home button).
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According to