There’s not true. There’s MMT which says that taxation is a money sink in an abstract sense. But that’s not a universally-accepted theory, and even if you do accept it it doesn’t say that taxes aren’t necessary. According to what I’m seeing on wikipedia, under “Criticism”, MMT proponents say they never said a government could spend without revenue.

Both MMT and more widely-accepted economic theories say that if the government prints money without bringing in proportional tax revenue that leads to inflation which gets to a similar result as not having money in the first place.

In practice the government has bank accounts that tax money goes into, and spending comes out of.

Classic MMT