Auto-filling fields when entering a dependent field

Good afternoon!
The following should be done:
There is a php page with fields (see below). photo
When entering the barcode, the fields: name and price are filled without reloading the page.

The barcode and the corresponding name and price are stored in the MySQL database table.

In the same page there are still fields with discount input and name output, which also need to be done.

I can mail the files.

I'll answer the questions, too.