Q. How to cite a letter from the Ministry of Health in APA Style?

APA Style (7th ed.)

If the letter is available to the public via a website, you could treat the letter as a free-standing web resource and note the URL in the reference. The APA Style Blog's resource on Archival Documents and Collections also explains how to reference letters accessed in print as part of a repository or collection. If the letter isn't publicly available, please use the format for personal communication and note the Ministry of Health as the author of the communication.. 

Reference

American Psychological Association. (2020). Publication manual of the American Psychological Association (7th ed.). https://doi.org/10.1037/0000165-000