I need to download capital one in my phone

This link may help you download if available in your country under the App Store. --> https://apps.apple.com/us/app/capital-one-mobile/id407558537

Have you tried to download it? What happens if you try? Are you getting an error message? If so, what does it say?

According to your post, you are still running iOS 14. Is that correct? If so, you may need to update your iPhone to iOS 16.4.1.