I set up a custom domain for my blog today! I decided to create a "blog" subdomain for my portfolio website elizabetholsavsky.com. To do this, I had to set up a new DNS record in Netlify (where my portfolio is hosted). The easy-to-follow instructions from Martin Patino in 'How to Setup a Hashnode Blog Sub Domain on Netlify' made the process a breeze.
Hashnode also has support articles for mapping custom domains to different sources including Namecheap, Cloudflare, GoDaddy, and Vercel.