Under USEF General Rules:
SUBCHAPTER 13-C MEMBERSHIP AND DOCUMENT REQUIREMENTS
GR1308 Membership and Document Requirements.
1 c.  Lessees are considered owners in connection with this membership requirement. When an entry is under multiple ownership, only one owner need be a Member or pay a Show Pass fee.  When an entry is under a minor’s ownership and training, the parent who must sign will be exempt from the Federation Show Pass fee.  Only a parent will be exempt from the Federation Show Pass fee if signing as coach for his/her minor child. BOD 1/11/20 Effective 2/1/20
Also please note when filling out an entry form:
TRAINER, as listed on the entry form, is defined as any adult (18 years of age & older) who has responsibility for the care, custody or performance of the horse while the horse is on the competition grounds.  This adult must sign the entry form as trainer.
COACH, as listed on the entry form, is defined as an adult (18 years of age & older) who gets paid for instructing, teaching, schooling or advising a rider with their horse on the competition grounds.  This adult must sign the entry form as coach.