Good question. It took me about 3 years of professional work before I felt comfortable defining myself as a designer.
Think about what you enjoy about design, what your style of working is, how you work with people, then craft a story around that. Try asking a few trusted and honest people about how they perceive you. They might not be right, but it could be enlightening.
Most designers can sketch, render, research, etc. Those are table stakes. Think about the intangible elements about you: leadership, empathy, vision, persistence, and how that shines through in your work.
As soon as I defined myself, I got a new job, and everything changed about my role as a designer. How do I keep my essence as a designer when trying to expand a wide breadth of skills beyond traditional design? What is my essence in the first place? Hard questions to answer.