@Merry Andrew,
Vitamin supplements aren’t really necessary for a normal, healthy adult although in the UK, official guidelines recommend that everyone over the age of 65 takes a supplement of vitamin D.
All of the vitamins and minerals that the body needs are either produced in the body, which means as long as the body is functioning properly it should be producing enough, or in the foods we eat.
By eating a balanced diet on a regular basis, there should be no reason for you to take vitamin supplements. A normal healthy diet is not something special; it is within the reach of almost everyone in Western countries.
UK guidelines describe such a diet like this: "A healthy, well balanced diet is one which contains plenty of fibre-rich starchy foods and fruit and vegetables, moderate amounts of meat or its alternatives, milk and milk products and only small amounts of foods and drinks containing fat and/or sugar."