Limit buy and sell orders placed via ActiveTrader can only be placed with an existing cash or crypto balance respectively. This means you may need to transfer cash or crypto funds to your Gemini account before placing your order.
US-based customers placing buy limit orders via the mobile app can place an order using ACH as a payment method. This will initiate a deposit from your linked bank to your Gemini account. These funds will be on hold until the order is filled or canceled. If you cancel the order the funds will be available to place another order or withdraw pending any ACH holds.