My macbook pro would not start and the screen is just black. The charger is plugged in but i dont know if its charging

It really helps to know the exact model of the laptop. You can get this information by entering the system serial number here:

Check Your Service and Support Coverage - Apple Support

I'm assuming you have a USB-C Mac as you don't mention the MagSafe LED. Here is an Apple article for troubleshooting USB-C charging issues:

If your USB-C power adapter isn't charging your Mac laptop - Apple Support

Unplug the charger from the electrical outlet for a minute in order to reset the charger's internal circuitry. Also try using another USB-C port especially on the other side of the laptop. Do you hear a "ding" when connecting the charger to a USB-C port...if not, there is some sort of hardware issue with the laptop or that port. If it is a 2018+ model, then it may need to be "Restored" which will destroy all data on the internal SSD and the process requires access to another Mac running macOS 10.15+. This is a procedure that Apple may even perform as well before replacing the Logic Board (also all data is lost when replacing a Logic Board because the SSD is part of the Logic Board).

Revive or restore an Intel-based Mac using Apple Configurator - Apple Support

Revive or restore a Mac with Apple silicon using Apple Configurator - Apple Support

I hope you have a good backup, because it may be impossible to recover any data from the laptop now especially if it is a 2018+ model.

Hello henrik165,

Thanks for using the Apple Support Communities!

If you're having trouble with your Mac not powering on as expected, the steps in the article listed above can help with that.

If those don't seem to improve this at all, you'll want to reach out to Apple Support directly to look in to some options for this.

You can reach out to them here: Get Support

Take care!