Debt monetization is also called inflation tax

When government deficits are financed through this method
of debt monetization the outcome is an increase in the monetary base, or the
money supply. If a budget deficit persists for a substantial period of time then
the monetary base will also increase, shifting the aggregate demand curve to the
right leading to a rise in the price level.When governments intentionally do
this, they devalue existing stockpiles of wealth of anyone who is holding assets
based in that currency. It is in essence a "tax" as the overall value of their
assets decrease due to a loss in spending power. This is known as "inflation
tax".
To summarize: a deficit can be the source of sustained inflation only
if it is persistent rather than temporary and if the government finances it by
creating money (through monetizing the debt), rather than leaving bonds in the
hands of the public.