Funding is provided by congressional appropriation. When congress says spend on something at this price, that is all that is required.
At that point the issue is whether the something is being used by the private sector. If it is then you have to stop the private sector using it somehow. Tax is one way of doing that, or you can just ban the private sector using that resource (nationalising healthcare for example).
Money isn't a thing, it is a unit of account. It grows and shrinks within the banking system as required to ensure all transactions that can be undertaken are undertaken.
Read Stephanie Kelton's Deficit Myth for details.
Funding is provided by congressional appropriation. When congress says spend on something at this price, that is all that is required.
At that point the issue is whether the something is being used by the private sector. If it is then you have to stop the private sector using it somehow. Tax is one way of doing that, or you can just ban the private sector using that resource (nationalising healthcare for example).
Money isn't a thing, it is a unit of account. It grows and shrinks within the banking system as required to ensure all transactions that can be undertaken are undertaken.