How do I handle catching one of my employees lying?

Let them know you know & see what they say or do.

Confront them and warn them that next time they will be written up

Confront him/her

Make him a manager or HR rep

Fire them!

If the lie affects your business, especially for client relationships, this could be a case to invoke "at will" termination (or other equivalent policies if not an "at will" jurisdiction). That said, there may be a matter of degree to be considered if a lesser infraction applies. Example: using PTO for a child's appointment or class play while claiming illness may call for discipline instead. Enforce established policies first, last, and always!

Tell your manager and let them deal with it

Ask to see the person privately. Present the facts and be patient to hear the employee explain their actions. Then give them a stern warning and be sure they know won’t tolerate lying.

Gather the facts and have a conversation with the facts in hand.

First, ask yourself why they may have lied to you. Are they afraid that if they told you the truth that you would have reacted versus responded? Can they trust you to be honest with you? Once you have diagnosed that, ask them if they trust you, and ensure them that you care about them and want them to succeed-which means having open communication at all times, no matter the situation. After you have both held each other accountable, come up with a strategy to prevent this from happening again, then address if there is any training that needs to be involved to accomplish this, put the game plan into action, and then see the results, respond, and reset. If it continues to be an issue, take appropriate measures.

Report to management

Talk to understand the reasons

wow, I would love to know this answer haha.

Ask them if they are okay - in a genuine way. Depending upon the infraction, it’s not always helpful to confront the lie exactly - as most often, the lie is a symptom of something greater and far more meaningful going on with the person. Try offering a genuine inquiry with compassion, free of judgment. This is far more likely to inspire a truthful response.

It's not my job to judge. Understand the shortcomings.

confront them with the proof