For healthier hair you may eat:

Fish: High in protein and omega-3 in addition to vitamin D: salmon and tuna are good examples

Dark leafy vegetables: high in iron, vitamin A, calcium and vitamin C

Nuts: Rich in biotin, protein, minerals and vitamin E; walnuts are good choice

Sweet potato: High in vitamin A,calcium, iron and vitamin C

Eggs: Rich in protein and biotin

Legumes: rich in biotin, protein, zinc and iron

Oysters: rich in zinc and protein

Milk and dairy product: rich in protein, vitamin D and calcium

Red pepper: Rich in vitamin A and C

Lean beef: high in protein and zinc

Sources:

https://www.verywellfit.com/top-foods-for-healthy-hair-2507141

https://tipsandbeauty.com/10-foods-for-healthy-hair-hair-loss-and-hair-growth/