It was many years before I ever heard this story told. Most people familiar with the Book of Mormon have seen the statements by the Three Witnesses and the Eight Witnesses as these statements are at the beginning of the Book of Mormon. At the time these witnesses took place, Joseph Smith and Oliver Cowdery had already completed the translation of the Gold Plates, and the Gold plates had already been returned to the Angel. Now with the help of the Whitmers, Joseph Smith, Oliver Cowdery were working on the translation of the Plates of Nephi. Nearing the end of the translation of the Plates of Nephi, The Three Witnesses where shown the plates by an Angel. The official historical account does not say who the angel was. One or two days after the account[1] of the Three Witnesses, eight other witnesses were shown the plates by Joseph Smith. Joseph’s Mother Lucy tells us that Joseph Smith received the record from an ancient Nephite[2] and then he subsequently showed the plates to the eight witnesses prior to handing them back to the ancient Nephite.
Much lesser known in history is the witness of Mary Whitmer, the mother of David and John Whitmer. This is taken from The Historical Record in October 1888, page 621.
https://archive.org/details/historicalrecord59jens/page/621/mode/1up?view=theater
STILL ANOTHER WITNESS
If the statements of persons who have always been considered reliable and truthful can be taken as authority, there is, besides the eleven witnesses of the Book of Mormon, still another one, who testifies to having seen the plates. This person is a woman, and if her statement is reliable, she is the only woman on earth who has ever enjoyed the privilege of seeing the holy treasure. Her name is Mary Musselman Whitmer, familiarly known as Mother Whitmer, she being the wife of Peter Whitmer, sen., and mother of five of the witnesses. Her son, David Whitmer, before his death, testified on several occasions that his mother had seen the plates, and when the writer visited Richmond, Missouri, a few weeks ago, John C. Whitmer, a grandson of the lady in question testified in the following language:
“I have heard my grandmother (Mary M. Whitmer) say on several occasions that she was shown the plates of the Book of Mormon by an holy angel, whom she always called Brother Nephi. (She undoubtedly refers to Moroni, the angel who had the plates in charge.) It was at the time, she said, when the translation was going on at the house of the elder Peter Whitmer, her husband. Joseph Smith and his wife and Oliver Cowdery, whom David Whitmer a short time previous had brought up from Harmony, Pennsylvania, were all boarding with the Whitmers, and my grandmother in having so many extra persons to care for, besides her own large household, was often overloaded with work to such an extent that she felt it to be quite a burden. One evening, when (after having done her usual day’s work in the house) she went to the barn to milk the cows, she met a stranger carrying something on his back that looked like a knapsack. At first she was a little afraid of him, but when he spoke to her in a kind, friendly tone, and began to explain to her the nature of the work which was going on in her house, she was filled with unexpressible joy and satisfaction. He then untied his knapsack and showed her a bundle of plates, which in size and appearance corresponded with the description subsequently given by the witnesses to the Book of Mormon. This strange person turned the leaves of the book of plates over, leaf after leaf, and also showed her the engravings upon them; after which he told her to be patient and faithful in bearing her burden a little longer, promising that if she would do so, she should be blessed; and her reward would be sure, if she proved faithful to the end. The personage then suddenly vanished with the plates, and where he went, she could not tell. From that moment my grandmother was enabled to perform her household duties with comparative ease, and she felt no more inclination to murmur because her lot was hard. I know my grandmother to be a good, noble and truthful woman, and I have not the least doubt of her statement in regard to seeing the plates being strictly true. She was a strong believer in the Book of Mormon until the day of her death.”
[1] https://bookofmormonheartland.com/the-encountered-traveller-going-to-cumorah/
[2] https://bookofmormonheartland.com/joseph-smith-testimony-of-the-eight-witnesses/