Start with the breed registration certificate
The anchor document is the registration certificate issued by the Paso Fino Horse Association. It records the horse's registered name, foaling date, sire and dam, breeder, sex and colour, together with the markings noted when he was registered. For a Paso Fino this certificate does more than prove a chain of ownership: it confirms the horse is a purebred, registered member of a gaited breed whose smooth four-beat gait is the whole point of the purchase, rather than a gaited cross of unknown background. Check the seller's name on the certificate carefully. The person selling the horse should be the owner the association has on record; if the certificate still names an earlier owner, the missing transfers need completing as part of your purchase, and you should not hand over the full price until that chain is resolved in writing.
The transfer form and the bill of sale
Registration only protects you once the association records you as the owner, so the sale should include a transfer form signed by the registered owner, with your name and address filled in as the buyer. Send it to the association promptly after the purchase rather than leaving it in a drawer, because a horse whose transfer was never filed becomes a paperwork problem for the next sale, the next show entry and any breeding record. Alongside it, get a written bill of sale even when you are buying from a friend. It should identify the horse by his registered name and description, name both parties, record the amount paid, and note any conditions agreed, such as a trial period or the horse being sold exactly as seen. Those few lines are what settle a disagreement later.
Health papers that should travel with him
The health file matters almost as much as the registration. Ask for a current negative Coggins result, the blood test for equine infectious anemia, which transporters, show grounds and boarding yards routinely require before a horse arrives. On top of that, expect a vaccination history, a deworming record, recent dental notes and anything from vet visits covering lameness, illness or ongoing management. If the horse is travelling across state lines to reach you, he should also arrive with the health certificate a vet issued for that journey. Note any identifier the certificate records for him, such as a microchip number, and where that record is held, so his identity can be confirmed years later without guesswork.
Check the documents against the horse
Papers describe a horse; the animal in the yard has to match them. Read the markings description while standing beside him and compare the white markings and hair whorls one by one. Scan the microchip if he has one and compare the number digit by digit. If you are having a prepurchase examination, ask the vet to confirm the horse's identity against the certificate as part of the visit, and to note anything on the health records that the seller has not mentioned. Discrepancies are far easier to sort out before money moves than after.
File everything where it can be found
Once the set is complete, keep it as one file rather than scattering it between the truck, the tack room and a kitchen drawer. Store scans of the certificate, the signed transfer, the bill of sale and the health records in his KinsLe Pet Passport, and the complete Paso Fino file is on your phone from the day he arrives, ready for the transporter, the new yard and his first vet visit under your name.