While it is possible to use a Function App, it would be better to either host your react app on blob storage as a static website.
Azure Static Web Apps is a complete service that is designed for Single Page Apps which you could leverage as well, but note that this is currently in preview and hence not recommended for production scenarios.
These options do not suffer cold start problems like Function Apps running in the Consumption Tier. But if you still require using a Function App in your scenario, prefer the Premium Plan to reduce cold start.