There is currently no minimum withdrawal amount. However, you will need to pay a withdrawal fee.
However, depending on the status of Ethereum Network, the ｍinimum withdrawal amount may be changed or withdrawals may temporarily take additional time to be completed.
In that case, this article will be updated.
About the withdrawal fee: https://socialgood.zendesk.com/hc/articles/6085681257369
Information on the withdrawal limit: https://socialgood.zendesk.com/hc/articles/6081856524313