An SSL certificate is the digital credential that proves your website is really yours and encrypts the connection between it and every visitor, which is what turns on the padlock icon and the https in your address. Without one, modern browsers put a “Not Secure” warning next to your web address, and many visitors leave the moment they see it.
For a small business, that warning does real damage: it appears before anyone reads a word you wrote, and it tells a first-time customer your site cannot be trusted with their details. A valid certificate removes the warning and keeps form entries, like a name and phone number typed on your contact page, private in transit. This is why people often say SSL certificate and HTTPS in the same breath.
I install and auto-renew a certificate on every site, tied correctly to your domain name and DNS so it never lapses. A visitor cannot trust a page a browser has flagged, so the padlock is a floor, not a feature, and it stays on from the first day your site is live.