So you set up your Joomla! site, made it live, and a few weeks/months/years later realised that you'd forgotten to enable the HTAccess file for SEF URL's. The end result being that rather than having a nice Search Engine (and user) friendly URL like /category/Blogs/post/, you instead have /index.php/category/Blogs/post/.
You could just enable the HTAccess file, but all the old URL's will return a 404. Not great if your site has already been indexed by search engines, even less great if you've got lots of inbound links on other sites.
It's actually incredibly simple to resolve, and in this post I'll be showing you the two easy steps you need to take to configure your site to redirect the old /index.php/* URLs to the nice SEF ones you want.