Is it possible anywhere on the internet to insert a song file and it would convert me to that song chords? I've been looking for Jesse Harper - Strangers chords and I can't find anywhere, I have his song but I can't find the chords for the guitar.
There's a few websites that claim to be able to do this Chordify is one I just found via Google. I have not tried it.
I've also run across Transcribe before. It's not online, but its purpose is to help you transcribe music, which is what you want to do. Again, I haven't used it, although I have seen it recommended by various online sources that are usually pretty accurate.
However, any automated system is likely to get it wrong. You can use them to give you a helping hand, but your best option is to use your ears. They're your most valuable musical tool, so take every opportunity to improve them! Play along to the recording, and try and find out what fits. Even if you find chords online, you should check them with the recording. You'll be surprised (or not) by the general accuracy (or lack thereof) of your typical chord chart.