My mother -n-law left me a house and other properties I only have one copy of the will what should I do to get a copy

If you cannot find the original, you can hire a probate lawyer who practice in the county in which your mother-in-law lived and died to help you probate (prove) the copy.  Because it is a copy, there must be testimony showing that it is a true copy.  This can be given by the two witnesses or by one witness and the notary or, if none of these people can be found, by two people who will not inherit and are familiar with your mother-in-law's signature.