1st question what is your age? do you suffer from any condition I should know about? or use any medications? Treatment depends on it. Below are the general recommendations for an adult.
Take a glass of milk daily but milk in tea does not count or substitute is ensure powder. Then 1 whole egg daily including the egg yolk, fish is also excellent source. Then there are vitamins that can be used once daily if you want only vitamin d and calcium tabs osteocare, cac 1000 is good, other than this the complete multivitamins include berocca, unicap-t, vitrum, theragran-m they can be used once daily. The other method is get a vitamin d(cholecalciferol) injection intramuscular once every month comes by name of miura-d, cara-in-d, g-cal, sunny-d.
But now very important question is why are you having a deficiency, either it can be decrease intake, decrease sunlight exposure, decrease synthesis by liver or kidney disease. So either kidney or liver or your GI system might be the source of the problem. So workup includes:
Renal function test( BUN, creatinine)
Electrolytes(sodium, potassium, free calcium, total calcium, chloride, magnesium)
Liver function tests( total and direct bilirubin, AST, ALT, GGT, ALP, albumin)
Serum PTH levels