Why is vitamin B12 mentioned when taking folic acid? — FITS Folic acid 400mcg tablets 60 pcs

The card does not mention vitamin B12 and does not explain why it is named when folic acid is taken. Only folic acid 400 mcg is given in the daily dose; apart from the reference to the packaging, the card names no other components.

General information (not a manufacturer's instruction): about combining folic acid with vitamin B12 and about tests before taking it, it is better to consult a doctor.