Posadas: Last Name and Heraldic Notes
A coat of arms was granted to a particular family line, not to everyone named Posadas, so a shared surname is a clue rather than a claim to the arms.
In the records
What can public data say about the Posadas family name? Quite a lot. In Wikidata, Posadas is listed as a Spanish surname.
Where a surname's origin is uncertain, as with Posadas, the best clues come from your own ancestors' parish and civil records. 3,554 Americans were listed as Posadas in the 2010 census. 77% of them identified as Hispanic or Latino. Spain's INE counts 1,525 residents with Posadas as first surname and 1,434 with it as second.
Research your Posadas family history with a full surname report and painted coat of arms.