WordPress is the most popular blogging engine right now. Many people use it for personal blogs, business, and even as a content management system. The default WordPress design looks old and outdated. There are quite a few very nice looking wp retro theme. Many of these are paid themes but there are also free ones.
The safest place to start your free theme search is to go to the official WordPress website. Do a search there for themes are there are literally thousands to choose from. You will need to download the one you like to your hard drive before you can install it to your site.
When you have the theme, you need to upload it into your WordPress installation. Find the wp-content folder, then click on themes. This is where you will upload the entire theme folder to in order to put it onto your site. Inside WordPress you need to enable that theme for it to work. If you don’t know how to upload, you will need FTP software to get this to work properly.
Many free themes have some rights that you need to acknowledge. Many times there are links that are in the footer that you need to keep intact that will link back to the author’s website or other sites. You should follow these rules in the theme license. Read it carefully so that you aren’t stealing anyone’s work. Generally speaking if you leave the footer area alone with whatever links intact, you will be fine.
You can also get themes at other sites on the internet. Just be careful who are downloading from. At time these free themes have some tracking tools in them that can spy on your visitors. The ones on the WordPress site are generally screened for such issues.