See this example properly formatted in the QUT Cite tool.
Personal communications include letters, emails, comments on message boards, verbal conversations and any other form of communication that is unpublished. You should only cite personal communications if they are authoritative and highly relevant to your assignment.
Your in-text citation should include:
In a conversation with J Smith (Apr, 2016)…
In a letter by Samanth Keogh (Prof., School of Nursing, Queensland University of Technology) dated June 2017…
In a post to Nurse Studio Blog (Mar 22, 2007) RS Grant commented that…
As personal communications are unpublished, they are cited in the text of your assignment but not in your reference list as they cannot be traced.
To reference a whole blog post see Internet sources - Blog.