Hi
As your iPhone will not charge, it may help to follow the steps here, including checking the charging port for any lint or other debris:
If your iPhone, iPad, or iPod touch won't charge - Apple Support
Also check that you are using either a genuine Apple cable or an Apple-certified / MFi cable. If you are already doing so, try instead using another such cable. Apple also recommends using genuine Apple USB Power Adapters.
If necessary, contact Apple Support (mail-in service may be available), make a Genius Bar reservation or visit an Apple Authorised Service Provider to arrange for your iPhone to be checked and, if service is recommended, to establish your available service options and any cost (whether under warranty or via chargeable service):
iPhone Service Answer Center - Apple Support
Service costs vary by region. In the US, for example, Apple's prices for iPhone 6 battery service and out-of-warranty service are currently $79 and $299 respectively (plus tax and, if required, shipping).