It looks like you referrting to the milestone that was paid to you for your contract. As Amanda has shared, milestone payments go through a 5-day security period before it becomes available to be withdrawn in your account. You may check out this help article for more information on how your earnings are processed.
I would also like to note that once you have earnings available on your account, you will need to initiate withdrawal of your earnings so that it can be transferred to your chosen payment method. Please refer to this link for more information on how you can withdraw your Upwork earnings.