When-ever you purchase a new puppy it is very good practice to take them into the vet with 48hrs. For one thing most health warranties require that you do this.
At your first visit to the vet, you will be asked to fill out their paperwork, have with you the DOB, your contract, and the health record from their previous vet. Also microchip information if they are already microchipped.
A good vet wants to have some assurance that this puppy is legally yours
There should be a through physical examination including but not limited to:
heart examination with the stethoscope
Each joint but for sure all major joints palpated and moved. If a male the vet should check to see if both testes are descended. Shoulder area and spine should be palpated. Knees should be checked
Checking for inguinal or umbilical hernias
Check to see if dew claws are present and a reminder to you to trim them.
Mouth - bite is checked - mouth is opened to see coloration of gums
Ears - examined and a "smell" check done.
Gait - a brief look at the gait of the puppy.
Eyes - should be looked at - you want to see clear bright eyes no discharge
Hope this helps out.