While "designer" is the most common term, you might also hear:
* Couturier: This term specifically refers to a high-fashion designer who creates custom clothing.
* Tailor: While traditionally a tailor alters existing clothes, they can also design and create custom garments.
* Stylist: Stylists focus on the overall look and feel of a person, often choosing and coordinating clothing for them.
Ultimately, the specific title will depend on the individual's role and the context of their work.