BibTeX:
@incollection{Various,
  author = {Various},
  title = {Letters from Around the World},
  booktitle = {Baha'i Stories Blog},
  url = {https://bahaistories.blogspot.com/2021/10/in-1920-pilgrim-becomes-aware-of-how.html},
}

APA:
Various. Letters from Around the World. In *Baha'i Stories Blog*.

MLA:
Various. "Letters from Around the World." *Baha'i Stories Blog*, n.d..

Chicago:
Various. "Letters from Around the World." In *Baha'i Stories Blog*, n.d..