How do I make my blog invisible to the web?

I’ve created a blog for a team project at work, and I need it to be completely invisible on the web so that it can’t be stumbled upon. I’ve just used a free account to make the blog and made sure to keep the checkbox unchecked that would make my blog visible to the community.

Are there any other measures that need to be taken? Is there an option to where the person visiting my blog can’t even read it without a password? The information will be very sensitive, so any additional precautions you all know of would be great.

Thank you

-Stradigos