The custodian for your account, Folio, processes client withdrawal requests generally within 6 business days.
When you confirm the amount that you would like to withdraw, Folio places an order to raise those funds by selling ETFs in your portfolio. It takes 4 business days for the trade to settle (Trade Day + 3 business days) which is the settlement period mandated by the Securities and Exchange Commission. Once the trades are complete, the funds will be transferred to your outside checking or savings account which generally takes 1-2 business days.
This same timing is also applied to withdrawing the funds from your Emergency Goal. For more information on the FDIC and the protections in place for your cash, please see this FAQ.