How do I migrate data from broken iPhone to a new iPhone?

You restore the last backup you made to either iTunes or icloud to the new phone during the setup process.

If your old phone was not backed up, anything that was not already synced to the cloud is gone.

You can’t transfer data directly from a non-functional phone.

Assuming you were using iCloud backup, you can restore the most recent backup to your new phone when you set it up using the same Apple Account and Password. If you weren't backing up, then you can't move the data over to the new phone and your data will be gone. Backups MUST happen before something unfortunate happens.

If you have been backing up, this link will help you --> Transfer data from your previous iOS or iPadOS device to your new iPhone or iPad - Apple Support