Open the PNG file in an image viewer or editor
Select Print or Export
Choose Save as PDF or Microsoft Print to PDF
Adjust page size, orientation, and scaling if needed
Save the file with a .pdf extension
On Mac, open the PNG in Preview, then use File > Export as PDF
On Windows, open the PNG, press Ctrl+P, then select Microsoft Print to PDF
On Linux, use an image viewer or a PDF printer option
Use an online PNG to PDF converter if preferred
Use a batch converter if you need to convert multiple PNG files