If your Star mC-Print 2/3 printer prints light text on receipts, you can adjust the print density as follows:
Download "mC-Print Utility" app.
Select your printer. Then go to Printer Settings.
Now go to Memory Switch Settings.
Find Print Density and adjust it (+3 for the darkest print). Click Apply.
To change print width, select Printable Area here and adjust accordingly.
Proceed with a test print.