To allow browser caching you need to edit your HTTP headers to set expiry dates on certain types of files. Get .htaccess file in the root of domain, this file is a secret file but should come in FTP clients like FileZilla. You be able to edit the htaccess file with notepad or any type of text editor.
Depending on websites, files can set dissimilar expiry dates. If certain type of files is updated more commonly, you would set an earlier expiry date. When you are completed save the file as it was and not as any other extensions.
Several URL Shortners are available such as bit.ly, tinyurl and goo.gl etc . You can manage more links and content in less space. It takes longer URLs and converts it into manageable links that almost never exceed 20 characters. In Social media or in Digital Marketing many links are long and wordy which is not optimum choice to share on Facebook and Twitter. Google and other search engine consider keywords in the URL for best result in SERPs but due to lengthy URL it creates conundrum for the users. URL Shortners in its own way work to collect all information and present a link with fewer characters.