Why Can't I Turn My iPhone On? Here's The Fix.
Did you test the charging cable by trying a different one? If the cable is working fine, try connecting it to iTunes on a PC or Mac and do a restore. If this does not fix your problem, try a DFU Mode restore by following this link: https://www.payetteforward.com/how-to-put-iPhone-dfu-mode/.
Please remember that, unless you have a recent backup, your data will be gone. If you have iCloud or iTunes backup on, some data like contacts may be saved.
But if all else fails, refer it to the third party authorized repair centers. You can check here if you have them nearby: https://locate.apple.com/