If you are trying to get a copy of your own plea agreement, it should not be difficult. However, if you are trying to get a copy of another person's plea agreement, it will depend on the rules in that particular jurisdiction as to whether the plea agreement is a public document. Sometimes judges will order that a plea agreement remain sealed, or secret, to protect the parties or the victims of a crime.
Ask your lawyer for a copy of your own plea agreement. If you are unable to reach your attorney, go to the courthouse where you entered your plea and ask the clerk for a copy. Bring your case number with you as that will make the search easier.
Go to the courthouse where the plea was entered, if you want to get a copy of a plea agreement that another person entered. You will need to know the full name of the defendant and, if possible, the case number.
Go to the clerk's office. The clerk will assist you in checking the file for the case. If the plea agreement was made public, you should be able to have a copy made by the clerk. There may be a small fee (usually less than $1 per page) for copying the agreement.