Caching (pronounced 'cashing') is a process in which data/files are temporarily stored in memory for better use of resources, and faster access.
It is basically done to improve the load speed of the website and make it faster for the users so that if the user is a returning user on the website, it will take him less time to load the website as compared to when he arrived for the first time.
If your product will be used on the web, one of the major optimizations will be how well are you able to leverage your browser cache memory. There are multiple ways in which one can implement caching mechanisms on thier product.
One of the easiest ways is to create an '.htaccess' file on your hosting provider and specify the expiration values for the same.