How does the fed control the levers?

Customer approaches commercial bank for a loan, bank assesses credit worthiness[1] and choses to make the loan. New money was “printed” into the economy.

What levers did the fed pull?

Also what function does the fed have in the tax part the GP mentioned?

[1] the bank has other depts looking at capitalisation constraints, another dept managing day to day operations of the reserve account, perhaps another dept managing funding sources etc. but the loan making function doesn’t consult them before creating new money to make the loan