By the way, in earlier, blogger used to generate posts URL automatically, but now it generates automatically as well as gives you to choose your custom URL. There would usually be post's title long and which could possible to be broken. So that type of broken link can be unfriendly for Google search engine and other search engines. This kind of problems would occur in earlier but now you have been provided an option where you can choose your own URL structure. This option has been very useful for niche blogger. Here is the process that you can apply to customize your post URL.
How to add custom URL on blogger posts?
Step 1: Log in to your blogger
Step 2: Create a new post
Step 3: Write some articles and there you see right side bar name post setting. You just click custom permalink.
Step 4: Put you own URL structure. And click on done.
Step 5: Publish it.
You've perfectly customized your blog posts URL. Now you can see your URL in the URL bar of your post article.
