Hi yes I just bought this iphone 8plus for a girl and it's say that the activation locked how do I unlock it

"Activation Lock for iPhone, iPad, and iPod touch" is a security feature, one aspect of which is deterring re-selling of stolen devices. To learn more click here --> http://support.apple.com/HT201365

An activation lock can only be removed using information for the account that applied the lock. If you know this information follow the onscreen steps to enter the Apple ID and password used to set up the device, or enter the device passcode.

How to remove Activation Lock - https://support.apple.com/HT201441

If you do not know the required information and you are not the original owner, get the owner of the account to remove the lock or return the device for a refund or recycle it. The device is otherwise useless to you. If the owner is unknown and has not provided contact information as a message showing in the login screen, there is no way to contact the owner unless the person who gave you the device knows them.

No iPhone 7

Please try restating your question and explain exactly what you are trying to do. Include whatever problems you are having and any error messages.