workers passively earn money for you, meaning that you will be making money by doing nothing, however you still need to claim money from them periodically. you can do this with
/workers claim, or by having worker notifications enabled. you will receive a dm with a button to claim money from your workers
you can buy, upgrade and claim money from your workers using
some upgrades for workers you cannot buy in the upgrade menu (launchpad, warehouse permit, nasa computers), you must find these in crates, or buy from other players on auction or through trading.