Without getting into all the technical stuff like CSS grid systems and the like. Responsive just means that your website can be nicely viewed on all devices including mobile.
Considering the majority are quickly moving toward doing much of their search and shopping on mobile devices – it will behoove the average business owner to have a responsive website. Google will also penalise you if your website isn’t mobile ready.
If your site hasn’t been coded to be responsive then you could well be losing sales and clients. Your old version is very difficult to read on the iPhone.
Having a responsive website makes it appear “fluid”. It automatically resizes images and videos as well as provides the content for ease of reading to your user. All this is without having to move to a .mobi
What does this mean for you? It means that your potential customer can readily see your phone number (TAP TO CALL) and not be frustrated by illegible information. If a person can’t easily see what they are looking for – they will look for another website that they can see.