Expungement/pardon
There are many questions on this forum similar to yours. Thus, I have prepared a standard answer.
Standard answer: Expungement is generally granted for illegal arrests or unlawful convictions. Generally, pardon mean you are forgiven for the crime but it remains on your record.
The usefulness or effectiveness of either procedure is generally worthless.
Check with the governor or attorney general of your state to see how you can go about either of these procedures. Check with the Attorney General or the President for federal expungement or pardon.
You must remember that there may be some private background check companies that have past offenses on their databases; those reports will never be expunged.
Stand by...others may offer more advice.