It depends on your plan. Tax law allows plans to permit “in-service withdrawals” by those who are still employed at the company maintaining the plan. However, plans are not required to offer this option. And if they do, there may be restrictions (e.g., an age higher than 59-1/2 or a certain number of years of participation). If a plan does not allow in-service withdrawals and you still want to take a distribution, see whether you qualify for a “hardship withdrawal” to pay medical expenses, etc. Check with your plan administrator.
Reporting income when actually or constructively received and deducting expenses when paid. Certain businesses may not use the cash method.