Any driver who obtains a CDL, or is hired after July 20, 2004 and has less than 1 year experience as a CDL driver must be trained in the following areas; Driver Qualification, Hours of Service, Driver Wellness and Whistle Blower Protection.
The certificate or diploma must show the following: The driver’s name; Date the certificate was issued; Name and mailing address of the training provider; A statement with the following sentence – I certify ________ has completed training requirements set forth in the Federal Motor Carrier Safety Regulations for entry level training requirements in accordance with 49 CFR 380.503; as well as, the printed name and signature of the person attesting that the driver has received the required training.
This document must be placed into the Drivers Qualification and History File, and must be retained for as long as the driver is employed by you and for 1 year after the driver terminates employment. (49 CFR §380 Subpart E)

Yes, as long as the physical has not expired and you retain a copy of the medical card on file.

Return the physical form and medical card to the doctor, and have him put the date in the correct space on the form and card.

No, the federal regulations state that drivers must be 21 years of age if they are going to operate across state lines a commercial motor vehicle with a gvwr or combination gvwr of 10,001 pounds or more. However, there is an exception for drivers of farm vehicles which allows drivers to be 18 years of age (found in part 390.5).