Tax is money that people have to pay to the government.
The government uses the money it gets from taxes to pay for things. For example, taxes are used to pay for people who work for the government, such as the military and police, provide services such as education and health care, and to maintain or build things like roads, bridges and sewers.
Taxes that are based on how much money a company earns are called corporate taxes
Taxes that are based on how much money a person earns are called income taxes.
Taxes that are based on how much a person buys are called sales taxes.
Taxes that are based on how much a person owns are called a property taxes. Things like houses have a property tax on them.
Taxes that are paid when official document are approved are called stamp duties (because in the past the document would have a stamp put on it). Changing who owns a house will often need a document approving.
Taxes that are paid when somebody dies are called inheritance or estate taxes.
Taxes are also usually split into 3 groups
Flat taxes: Everybody pays the same percentage. Russia has a flat income tax and everybody in Russia has to pay 13% of the income.
Progressive taxes: The more money a person makes, the higher percentage of their income they have to pay. Most countries have progressive income taxes.
Regressive taxes: The less money a person makes, the higher percentage of their income they have to pay. Sales taxes are usually called regressive as poor people spend a higher percentage of their money, than rich people.