Check out this explanation of creating a 3D twin-tail hairstyle by 3D Artist 0から始めるblender生活, inspired by the anime graphics with Blender, a free 3D software for modeling, texturing, rendering, animation, and VFX.
First, the artist created the main parts to match the original illustration using curves and subdivision, focusing on the silhouette. The next step was to convert it to a mesh and join it together.
Take a look at more works looking like 2D anime-style renders, while in fact being three-dimensional models:
