Iphone 6s Plus won't turn on?

Since last night, my iphone won't turn on, it has the apple logo on the screen but it doesn't move from there. Sometimes it goes black then back to the logo screen forever. It was charging all night and my cord does work. I don't know what to do.

Probably leave it for a few days then try again.

It is on boot loop and the only way to fix it is by erasing every single data in the phone via recovery mode (look it up its hard to explain) but I recommend waiting for a few days or weeks to see if it still comes on if it doesn't then erase it there's no way to save your files from it unless you have backups then just erase and backup from iTunes.

Take it to an Apple Store.