If you are working from an Illustrator file, while it is possible to export as a PNG from Illustrator, we do not recommend exporting the artwork from illustrator. It is best to export the artwork as a Photoshop document first and then saving it as a PNG from Photoshop.
To export the Illustrator file as a Photoshop file, Go to File> Export and select the ‘Export As’ option. Select Photoshop as the file type and save. In the next box select ‘write layers’, this will make the file more editable in Photoshop.