This will be a short post. We know nothing about her, except that she married Daniel Kramer in Pennsylvania about 1765 and that she had 12 children. We have a death year, but no date, of 1813 in Haines, Centre County, Pa. That's what we know about Anna Maria.
In looking at the trees that are on line, I think there is probably an error. "Everyone" is listing her as born in 1755, yet her children were born starting in 1766. It seems more likely that she was born sometime between 1745 (or perhaps earlier) and 1750. So she was likely born in Pennsylvania before records were kept or survived, or in Germany and came as a young child. For instance, the ship "Samuel" from Rotterdam in 1737 carried a Johann George Geis who was 28 years old. This particular manifest seems to list only men, but it is likely there were women on board, too. I'm only suggesting that this or another Mr. Geis may have brought children with him who were undocumented upon their arrival. Or, again, she may have been born in Pennsylvania. We don't even know for sure that this was a German family, but I've not found evidence of a family of that name from any other country, in that time period.
The names of two of her sons who don't seem to be named for the father's line were Johann Jacob and Johann Philip. One of those names may someday provide a clue. Perhaps one is a father or a grandfather's name.
For the moment, my research for her parents and siblings is at a stand still but I hope that by writing this post someone may see it and have some information they'd be willing to share. At the very least, I hope this alerts someone searching for Anna Maria that her birthday is likely not 1755!
The line of descent is:
Daniel Kramer-Anna Maria Geis
Anna Maria Kramer-Andrew Kepler
Mary Kepler-George Harshbarger
Lewis Harshbarger-Catherine Mentzer
Emmanuel Harshbarger-Clara Harter
Grover Harshbarger-Goldie Withers
Cleveland Harshbarger-Mary Margaret Beeks