It depends on your age. If you are 59.5 years old or older, yes. If not, then no, a withdrawal results in a 10% penalty. If you would like for that money to be available to you before 59.5, then I would consider a standard brokerage account.
That’s not really how it works. Are you rolling it over from a Roth 401k? Either way unless your at retirement age, you can’t just pull it out penalty free.