I give gift (Iphone6) I dont know old Apple ID .

If you mean that you've been given the phone and it's locked to the previous owner's account then you will have to contact that person and ask him/her to remove the phone from their account (nobody else can remove the phone from their account, including Apple) : Turn off Find My iPhone Activation Lock - Apple Support

If Settings > iCloud > Find iPhone is 'on' you won't be able to remove that account from it - you will have to contact the person that you got it from, only he/she can potentially help you