First, I have to use the conditional code of Blogger to select a particular page or post, once we select the page that we want to redirect, we will apply meta code to redirect.
Don't think so much, Just copy the below code and paste it just below to
<b:include data="blog" name="all-head-content"/>
code inside your Blogger source code.
<b:if cond='data:blog.url == "Your-Blog-Post-URL-HERE"'> <meta http-equiv='refresh' content='0;url=External-Post-URL-HERE' /> </b:if>
Change your blog post URL and the external post URL in above code, and save the template. Now, go to the post that you have redirected, you will see once it loads, redirected to the external domain post page. If you have any doubt you may feel free to contact us.