It depends on the situation. In daily life, the preferred route is consistent dietary intake (leafy greens and, when appropriate, fermented sources). In clinically significant deficiency or bleeding risk, clinicians may prescribe oral vitamin K or administer it by injection. Newborn prophylaxis is routine to reduce bleeding risk. In adults, underlying causes (malabsorption, antibiotics, liver disease) should be addressed. For patients on warfarin, vitamin K must be managed with INR targets in mind. In short, administration is individualized and monitored.