An acquisition record documents the event through which a specific collectible entered a person's or organisation's collection. It should connect the object, the source, the acquiring owner, the method and terms of transfer, the date or sequence of dates, and the evidence supporting what happened.
This is the documented starting point for the current owner's ownership history. It may be a detailed auction packet, a private-sale receipt, an executor's distribution schedule, a gift letter, an online order record or a carefully labelled retrospective note. Its quality depends less on formality than on whether it is specific, attributable, honest about uncertainty and reliably linked to the physical object.
A strong record does not merely say, “I bought this.” It shows that this identifiable object was obtained by this identifiable owner, from this identifiable source, through this documented transaction, on these terms, with this evidence and subject to these known gaps.