Short answer — for most people in Singapore the ZALORA app is the best all‑round option for Muslimah fashion (largest selection of modest-wear and local brands). But the best app can vary by need — see quick picks below so you can choose by style, price and purpose.

Top picks

• ZALORA (best all‑round: selection + convenience) — big dedicated “Modest / Muslimah” category with local labels (Naelofar, LÚBNA, NH by Nurita Harith, etc.), fast Singapore delivery and standard return policies. (zalora.sg)
• FashionValet / dUCk (best for curated/modest-designer labels and premium scarves) — FashionValet carries specialist modest labels and has a Singapore presence; dUCk (the scarf label) also has its own app for premium hijabs and accessories. (womensweekly.com.sg)
• Shopee / Lazada (best for budget variety and frequent deals) — huge marketplace selection of hijabs, abayas and everyday Muslimah pieces at wide price points; good for bargains but check seller ratings. (lazada.sg)
• Carousell (best for pre‑loved, local and one‑off pieces) — great if you want second‑hand baju kurung, branded hijabs or local sellers you can meet/inspect first. (carousell.sg)
• Brand apps / local boutiques (best for signature pieces) — if you want specific labels (Naelofar, Sufyaa, Ayu Apparels, Qudwah, etc.) buy via their official stores or apps for latest drops and authentic stock. (mcstaging-my.naelofar.com)

Which to pick (short guide)

• Want curated designer modest wear or Raya/occasion outfits → FashionValet or ZALORA. (womensweekly.com.sg)
• Want premium scarves/hijabs and accessories → dUCk (brand app) or Naelofar official channels. (apps.apple.com)
• Want the cheapest options or many sellers/fast promos → Shopee / Lazada apps (compare seller ratings). (lazada.sg)
• Want second‑hand or rare local finds → Carousell. (carousell.sg)

Quick shopping tips

• Check seller ratings, delivery times and return policy before checkout (marketplaces vary). (lazada.sg)
• For branded scarves, buy from the brand’s official app/site or authorized stockists to avoid fakes. (mcstaging-my.naelofar.com)

If you tell me which style, budget, or item you want (everyday hijabs, abayas, baju kurung, prayer sets, or designer pieces), I’ll give a single best app recommendation and a couple of specific stores to browse.