Hi,
AEM is a product that can be integrated with any other software product, and that's precisely why there is no official documentation for each of the different available software products. Therefore, you won't find a definitive guide on how to integrate Stripe with AEM in this case. However, integrations between products often share similarities. My recommendation would be to refer to a general integration guide: https://docs.stripe.com/development and determine which integration method best fits your needs. In most cases, the easiest approach is to utilize the product's (in this case, Stripe's) REST API.
Check these threads as examples:
https://experienceleaguecommunities.adobe.com/t5/adobe-experience-manager/aem-sprinklr-integration/m...
https://experienceleaguecommunities.adobe.com/t5/adobe-experience-manager/aem-mulesoft-integration/m...
Hope this helps
Esteban Bustamante