The htaccess file is a configuration file which is used on Apache based web servers to control many features of the server. For example, you can make friendly urls, protect files, redirect urls...etc with htaccess.
We use it when we do on-page SEO like friendly urls for your websites, redirect url errors ...it's useful for websites at the moment.
.htaccess is a configuration file for use on web servers running the Apache Web Server. When a .htaccess file is placed in a directory which is in turn loaded via the Apache Web Server, then the These .htaccess files can be used to alter the configuration of the Apache Web Server software to enable/disable additional functionality and features that the Apache Web Server software has to offer. Htaccess help in basic redirect functionality, for instance if a 404 file not found error occurs, or for more advanced functions such as content password protection or image hot link prevention.
To add a little bit more understanding to this thread I think it is important to remember WHY htaccess files are used.
In shared environments hosts cannot (or at least shouldn't....) allow their users to make modifications to the httpd.conf. This httpd.conf is the webserver / Apache configuration file that contains very important information needed to make everyone's site load as they should.
Apache introduced these htaccess files as a way to allow users of accounts their own way of adding custom configurations. Whether it be redirects (most common), or setting up custom account level variables such as memory limits and PHP configurations - look no further than your local htaccess file!
Here is a link where you can read more about htaccess files:
Pay VERY close attention to the "How directives are applied" section. Very important. Also please refer to htaccess entries as directives to seem more ... professional
.htaccess file is an important part of every website. If configured wrongly, it can block spiders and visitors from viewing website.
As far as SEO is concerned, it can be used to GZip a website AND also used to activate CDN (content delivery network) like cloudflare. These two techniques help to enhance the loading speed of any website and thereby help to enhance SERPs.
A .htaccess (hypertext access) file is a directory-level configuration file supported by several web servers, that allows for decentralized management of web server configuration. They are placed inside the web tree, and are able to override a subset of the server's global configuration for the directory that they are in, and all sub-directories.
The original purpose of .htaccessâ€”reflected in its nameâ€”was to allow per-directory access control, by for example requiring a password to access the content. Nowadays however, the .htaccess files can override many other configuration settings including content type and character set, CGI handlers, etc.