What is Cloudflare access? If my application consists of only API do I need it?

Hi, I’m new to Cloudflare

My workplace already adopts using Cloudflare access for one of its web apps. It uses the one-time pin feature to email.
Currently, a new API application is being developed and my employer suggests using Cloudflare access for it. The API will be used in mobile apps.

I already did some search and found this https://blog.Cloudflare.com/leave-your-vpn-and-curl-secure-apis-with-Cloudflare-access/
In the above page, there’s a mention about identity provider to log in. Does it mean that the mobile app has to open an authentication page externally everytime its needed? Can I extend the duration of the authentication session? Can I still use the one-time pin for this use case?

Is API application is intended use case for Cloudflare access?