If you are still employed by the plan sponsor,
You must ask your employer for a hardship withdrawal. The employer decides what hardships they will permit. If you do not have a permitted hardship and you lie to your employer, your employer could take action against you. If the IRS audits the employer and finds that they are not following the hardship rules correctly, the employer can be severely penalized.
If you are no longer employed by the plan sponsor,
You can withdraw at any time for any reason.
With any withdrawal (hardship or not) you will pay regular income tax. You will also pay a 10% penalty unless you have one of these reasons that qualifies for an exception.
https://www.irs.gov/retirement-plans/plan-participant-employee/retirement-topics-exceptions-to-tax-o...
