Is there a penalty for withdrawing from a brokerage account?

Excuse me, I have a question regarding brokerage accounts. I'm wondering, is there any sort of penalty or fee associated with withdrawing funds from a brokerage account? I understand that there may be different rules and regulations depending on the specific account and brokerage firm, but I'm curious if there's a general rule of thumb or any common practices that I should be aware of. I'd appreciate any insight you can provide on this matter. Thank you.