You can use top soil for the top 2 inches of ground. The most important functions are that it is supporting the roots, transporting nutrients and oxygen and clearing out any extra water in the soil.
The advantages of top soil are that it is inexpensive and that you can buy it in small quantities. The disadvantage of top soil is that it sometimes contains seeds, fungus and viral diseases.
It is very important to know that plants need air and that they do not grow well in airless conditions. So, before putting the soil in the planter make it loose and light.