If you have a criminal history, then it can effect a number of different aspects of your life. It can effect your job, or your ability to obtain employment.
There are two ways to try to remove or seal your criminal record if you are eligible. The first is an expunction. If you were arrested for an offense and acquitted at trial or the case was dismissed, refused, or no-billed by the grand jury then you will not have a conviction on your record. However, the fact that you were arrested for the offense will always be on your record until you get an Order signed by a judge on a Petition for Expunction.
If the case is dismissed, no-billed or refused by the District Attorney then you must often wait until the statute of limitations runs before you file. If you are acquitted, or the prosecution has become barred for some other reason like res judicata or collateral estoppel then you are immediately eligible.
If you were placed on deferred adjudication for most offenses then you can file a petition for non-disclosure asking the court to seal your record. For some offenses, there is a waiting period. For many offense, you can file the petition upon your discharge and dismissal from probation.