Give us context. If you are reading a tax protester book that says the government can only do direct and indirect taxes and therefore income isn't taxable, you need to get another book.
There are income taxes.
There are direct taxes on property you own.
There are indirect taxes on property you buy.
(If you have to classify the income tax, you'd call in indirect.)
All of these are LEGAL
I hope my answer has come to your help. Have a nice day ahead and may God bless you always!