Native, cross-platform, or a mobile website
Three roads
Native. Separate code for each operating system. The best access to hardware, performance and system feel. Nearly twice as expensive to maintain.
Cross-platform. One codebase for both systems. Very mature today, and suits most business apps.
Mobile website. No store, instant updates, a shareable link. Limited in hardware access and notifications, but enough for many cases.
What actually decides
Ask what's needed from the device: an advanced camera, sustained background work, location streaming, sensors, deep system integration. The heavier the answer, the more the scale tips toward native.
Ask about the team too: two developers won't maintain two native codebases without paying for it in pace.
The cost that isn't in the code
App stores add a whole world: approvals, signing, a privacy policy, reviews that reject versions, and waiting time. Plan a release path in advance and don't promise a date that depends on an external party's approval.
Going deeper
If you're unsure, a mobile-optimized site is usually the right first step: it validates demand without a store's entry fee. The move to an app is made when there's a proven need for notifications, offline work or hardware access — not in order to “be in the store.”