It looks like the website is using HTTP authentication. In that case you should be able to provide the authentication details as part of the URL similar to:
https://username:[email protected]/login.html
I last used this feature about 15 years ago. Back then, Netscape Navigator hid the password by displaying the URL for the rest of that authentication realm (website) as:
https://[email protected]/
Chromium also support(ed) usernames and passwords in URLs for HTTP authentication. If the displayed user name is not sensitive information, this solution could suit your purposes. However, support for passwords embedded in URLs was removed in version 19, reinstated in the following release and later removed again.
Note: Including passwords in the userinfo part of a URI was deprecated in RFC 3986deprecated in RFC 3986, the official specification for the syntax of Uniform Resource Identifiers (URIs).
Related ServerFault question: Can you pass user/pass for HTTP Basic Authentication in URL parameters?