Milei wants to cut 15% of the GDP from government spending.
According to the latest data available Argentina spent around 15% of it's GDP on the state.
The easiest expenses to reduce are subsidies (specially energy subsidies) and maybe getting rid of some of the state owned enterprises. Aerolíneas would be a good start. Social security payments will also likely be affected.
Agree with the first, but not the later, as Milei has said the only thing the wallet is open for is social plans/pensions.
My guess is across the board things like attrition/voluntary buyouts/early retirements/wage freezes for public employees, subsidy reductions for the wealthier income brackets, etc. We'll know more tomorrow apparently.