You can access your funds any time by messaging "Withdraw" to Digit. The funds you request to withdraw usually settle next business day. There are no limits on how much or how often you can withdraw.
If you'd like to withdraw from a Goal, message "Withdraw Goal" or use the emoji you assigned to your Goal (e.g. "Withdraw ⚽️ ").
Here's a list of all of the commands you can use with Digit.