The phone will not power up.

@eveshe, Shelly, Ensure your iPhone is fully charged, force your device to restart by pressing and holding the Sleep/Wake (Power) button and Home buttons together for 20 seconds until you see the Apple logo(info. from 1st link below has more steps/info.), 1st and 2nd link with more trouble shooting tips for your iPhone 6 . If battery not wanting to charge, try another compatible charger, still not charging check the charge port for dust/debri/damage, blow/pick out dust/lint etc., if pins look bent straighten very carefully with tooth pick. If all looks good probable bad battery( use guide below to replace battery). Good luck. I hope this helped you out, if so let me know by pressing the helpful button.

https://www.ikream.com/2017/05/how-to-fi...

iPhone 6 Troubleshooting

iPhone 6 Battery Replacement