I downloaded mVisa sdk:
1) Acquirer SDK to enable merchant experience
2) Acquirer or Merchant SDK for QR generation
but I do not know how to use them. Where can I find documentation on them?
Thanks for inquiring about the Visa Direct mVisa API. Before moving forward, it is important to review the Visa Direct documentation via this link - https://developer.visa.com/capabilities/visa_direct/docs
In particular, please see the top few paragraphs that are shaded in yellow that discuss the requirements to use Visa Direct. After having read the documentation, if you meet those requirements, then please click through the link in those paragraphs to the Visa Direct Program Implementation Questionnaire, fill it out, and submit to the email address listed on that form. Please let us know if you have other questions.