He wears lifts. Confirmed by several people who have worked closely with him including Noel Casler who worked with him on The Apprentice and made many public statements about Trump’s drug use, adult daiper use, lifts and frequent self-soilings - and has still not been sued by lawsuit-happy Trump 6 years on.

https://www.politicalflare.com/2019/09/insider-claims-trump-wears-adult-diapers-due-to-incontinence-from-repeated-stimulant-abuse/