Building a new website from the ground up or redesigning an existing website to meet specific goals such as increasing conversions requires web design.
If you are building a brand new website and don't have much experience, it may be best to hire a web designer. A web designer can structure the site, organize the flow, and make everything look and work great so that all you have to do is put in your quality content.
If you already have a website that's doing okay but you're noticing a high bounce rate or not as many people are discovering the site as you may have expected, it may be time to redesign your existing website with the help of a web designer. It can be hard to pay money to do something that you already did once, but the improvement in conversion may well be worth it.