The four characteristics of a good tax are: simplicity, which means that tax laws should be easy to understand; economy, which means that the government should be able to collect the tax without spending a lot of time fo rmoney; certainty, which means that the taxpayer should know how much they will have to pay; and equity, which means that the tax should be fairly assessed.

Vertical equity  is referred to as or known as the notion that the taxpayers that have the greater ability to pay the taxes should pay the larger amounts.

Whereas on the other hand the horizontal equity  refers to the idea under which the taxpayers that have the similar abilities in accordance with paying taxes should pay same.

Regressive tax  is known as or described as the tax under which the high-income earner pay the smaller fraction of income as tax than the other low income earners.