Will she be required to declare that phone?

Gerard, if she declares at the customs, she will be required to pay 10 percent of its price as duty. If she didn't, she has a chance to avoid the duty. But there is a chance that she might be caught by the customs. At that moment, 10 percent duty can't be escaped.

If she takes it for her family member, then she can throw away the box and bring the phone and charger. It's normal that a person has two phones. In this case, the tax can be escaped.