What are the different types of makeup brush fibers, and how do they affect application? How do I know which brush shape to use for each product?

Makeup brushes are typically made with either synthetic fibers or natural animal hairs (such as goat, squirrel, or sable). Synthetic brushes are ideal for liquid and cream products because they don't absorb product, they're easier to clean, and they're cruelty-free. Natural-hair brushes have microscopic cuticles that hold onto powder products better, making them perfect for blending and buffing powder formulas. Some brushes also use a hybrid blend to combine the best of both.

Different brush shapes are for different purposes. Brush shapes are specifically designed for different purposes: 

Flat/paddle brushes – for packing on foundation or concealer.

Domed/fluffy brushes – for blending eyeshadow or buffing powder.

Angled brushes – for precise lines (eyeliner, brows, or contour).

Tapered/pointed brushes – for detail work like inner-corner highlighting or spot concealing.

Fan brushes – for sweeping away fallout or applying highlighter in a sheer wash. Using the right shape ensures better control, placement, and finish.