How do I fix the "Not Secure" warning on my site?

The "Not Secure" warning means your site is on HTTP instead of HTTPS. Fix: install an SSL certificate. Most modern hosts (Squarespace, Wix, WordPress.com, Shopify) include this free. For self-hosted sites, use Let's Encrypt (free) or your host's SSL service. After installing, set up a 301 redirect from HTTP to HTTPS so old links still work. Takes 15-30 minutes total.