my iphone exploded!!

We are not Apple. This is a user forum.

Nearly every case of an incident like this can be tied to a defect or improperly installed 3rd party battery or liquid damage.

What country do you live in?

In addition to what KiltedTim explained, leaving a charging phone, especially a very old one, on a soft surface (or worse, under a pillow or blanket) while charging is always a bad idea.

From the sound of the original post, they charged the phone at night ("it was charging just like every night") on the bed ("it burnt my pillow my planket"). Especially if the phone was already getting hot while being charged (and I bet it was even before this), charging it on a soft surface was probably a bad idea.

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I don't see a cable in any of the photos.

The battery is mostly melted.

Charging on a flammable surface was a recipe for disaster. The OP evidently lives in a country not supported by Apple, so I'm not sure what they think Apple can do for them?