From Colonial times, having the actual original copy of a deed was very important to prove ownership. Today, when there is a transfer of ownership, deeds are (almost always) recorded in the couthouse of the county where the property is located. The answers you already received address this typical modern situation, where seller cannot find their copy of the deed.
IF in fact deed was not recorded at the last transfer, you probably need an attorney to help sort out ownership and chain of title.
Hope that helps.
Good luck with selling your property !
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