How to use this app on my MacBook after purchasing on my iPhone

Hi,

The mobile subscription of the Acrobat Reader mobile app cannot be used on Mac/Windows. To use the premium subscription on a Desktop device, you need an Acrobat Pro DC subscription. However, with Acrobat Pro DC desktop app subscription, you can use the premium features on the phone.

For more details, refer to: https://helpx.adobe.com/acrobat/mobile-app-faq.html

Let us know if that helps.

Thanks,

Harsh