I have a site built using the browser version of Wordpress. I'd like to build and manage another website but use the same Wordpress account.

For example, I'd like to manage the domains and edit the pages for www.websiteA and www.websiteB.

Sorry if this is a naive question. I can always make another Wordpress account but I'd like to avoid managing multiple accounts for each page I build.

Would I need to install the Wordpress software on my computer and manage the websites from my own server?