Should multivitamin capsules be taken after breakfast ordinner and should they be taken with milk or water?

How about not at all: No clear convincing rct studies demonstrate any benefit from taking multivitamins, much less timing & fluid. Current recommendation is to eat a balanced diet w/lean protein, plenty of fruits & veggies, nuts, olive oil, etc, avoiding red meat, refined carbs & processed food. This is basically the mediterranean diet. Don't forget regular exercise. Focus your attention on this, not multivitamins.

Best after breakfast: I advise taking multivits after breakfast, as b vits. Can be stimulating & if taken late might cause insomnia. Water or milk makes no difference. While taking a multivit. Is no substitute for a healthy diet, most americans are deficient in calcium, magnesium, folate, (folic acid) chromium & vits. A, d & e. Recent research showed 8% reduction in cancer risk using a mediocre multivit.; a good one should help more!

Any is OK.: Unless the bottle says otherwise it is reasonable to take it when it is most convenient for you.

Either: Multivitamins should be taken with a meal and on a schedule that encourages their regular use. Most people find that taking them with breakfast is a good habit especially because having daily breakfast is shown to decrease overeating later in the day.