Google is your friend:

https://en.wikipedia.org/wiki/Responsive_web_design

Responsive web design basically means a website designed to adjust different device screens example desktop, tablet, mobile or even a smart watch. When you building a website it's highly recommend to take this in account and always go for perfecting responsive site before creating a mobile app version if you have to.

If you’ve been following digital marketing, you will have seen that the experts have called out “the year of mobile” pretty much every year for the past 4-5 years. This is an attempt to capture the increased usage of mobile devices to browse and shop online, and the importance of everything from mobile advertising to mobile content and experiences now that mobile traffic accounts for more than half of internet traffic.

At the most basic level, being ready for this new world of mobile means having a website that is optimised for mobile. There have been different ways to do this: you might have a desktop version and a mobile version of your website; you could have a website plus a mobile app; or you might have one single website with a responsive design. I’ve been a fan of responsive web design since 2012 and it’s proven to be a very effective solution.

Responsive web design means that you create one website that adapts to different screen sizes. Effectively, what you are doing is defining rules that change the layout as the screen size changes. If you imagine starting with a website that you’re viewing on a big desktop screen, as you reduce the size of the browser the layout will adapt accordingly. Content that was in a sidebar on the right might move to below the main content; at a certain point, the menu might collapse completely into a drop-down “burger menu”; fonts and buttons might increase in size to make it easier to interact with them on a smaller touch screen. Some designers might even create the website “mobile first”, i.e. start by designing something that is fully optimised for a handheld device and then create rules for larger screen sizes.

Ultimately, it’s about creating the best possible user experience, however they are accessing your site.

Get in touch if you’d like to discuss if this is the right solution for your business!