While availability varies by location, these stores are your best bet for finding a physical box or USB installer: Windows 10 Pro Key - Walmart
Buying a retail version of Windows 10 in a physical store is increasingly difficult because Microsoft stopped selling it directly on its website in early 2023. However, as of , limited physical stock and third-party options remain available at major electronics retailers. Recommended Retailers for In-Store Purchase where can i buy windows 10 in store