Family coat-of arms were primarily used in battles so that opponents could identify each other.
Historically - the design was only awarded to an individual and only they could use it.
Other times, it was allowed to pass to their descendants, evolving in design to denote family position, alliances, marriages, etc….  And exactly who had a right to use coat-of-arms
varied between countries, by law or social convention.
SurnameCrest uses historical sources; documents, records and books to replicate the original, the coat-of-arms that relates to the earliest-known bearer of the name on record. This would be the original before being changed by marriages etc... by later generations and different branches of the family.