To learn UI/UX design for free with a certificate, one of the most popular options is the "Google UX Design Professional Certificate" on Coursera, which provides a comprehensive introduction to user experience design principles and allows you to earn a certificate upon completion, even with the free trial period on the platform.

Platform: Coursera

• Focus: Fundamentals of UX design, user research, wireframing, prototyping, testing
• Cost: Free to access with a Coursera trial, then a monthly subscription fee

Other platforms to explore for free UI/UX courses with certificates:

1. LinkedIn Learning: Offers free introductory courses on UI/UX design
2. Skillshare: Provides free classes on UI/UX design with various instructors
3. IBM SkillsBuild: Features a free UX Design course with a certificate
4. Microsoft Learn: Offers free modules on UX design with a potential certificate