Follow along with the video below to see how to install our site as a web app on your home screen.
Note: This feature currently requires accessing the site using the built-in Safari browser.
If you are still using CentOS 7.9, it's time to convert to Alma 8 with the free centos2alma tool by Plesk or Plesk Migrator. Please let us know your experiences or concerns in this thread: CentOS2Alma discussion
Starting from version 10.3.1, the ServerAlias "www.<DOMAIN.TLD>" record is added to the webserver configuration for each domain without depending on its DNS zone content.
So, www prefix works by default for any new created domain.
To my opinion your problem isn't about www prefix. You are simply trying to setup a redirect or alias. The best way would be to setup redirect on "blahblah.com" or make it assigned to the same folder blahblah.com.myshopify.com. The first option would cause URL changed to blahblah.com.myshopify.com, the second option would keep URL preserved.
Indeed you cannot make "blahblah.com CNAME" in blahblah.com zone since there is already mandatory "blahblah.com A" record for it.
Create a .htaccess file with the below code, it will ensure that all requests coming in to domain.com will get redirected to www.domain.com
The .htaccess file needs to be placed in the root directory of your old website (i.e the same directory where your index file is placed)