how can i host my HTML site and link my custom domain from NameCheap to it on Netlify
What you wish to do is entirely possible.
First, choose the deploy method you wish to use, such as drag and drop, git, or Netlify CLI. See:
Next, decide whether you wish to use Netlify DNS, or use Namecheap DNS and configure the custom domain externally. See this support guide to decide which is best for you.
If you wish to use Netlify DNS check out
and also the Netlify DNS documentation
If you wish to use Namecheap, check out the configure external DNS documentation
If you have any questions or issues, do not hesitate to reply.