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No, not necessarily, but it can cause a minor issue. iPhones use a Lithium-Ion battery for its power, using while it's charging won't necessarily ruin the battery, but if you're using the phone while the battery is in the charging process, it can cause the phone to think it has more power than it actually has.
Myth 5: Don't charge your phone until it's completely dead. The truth: It's better to charge your phone every day than to do a  deep charge  from time to time. Lithium-ion batteries, like the kind used in Samsung and Apple products fare better when they're charged. If you constantly let them drain to 0%, they become unstable.