Hi @Chan, Johnny ,
By "require username/password" do you mean a website that requires login? Or do you mean monitoring a website with a specific username/password?
SCOM has the capability to monitor websites with specific usernames, you can achieve this by creating a Web Application Transaction Monitor.
If you want to monitor a website that requires you to log in to the website to check if the login works, then I'm afraid SCOM doesn't really offer any builtin capability for this, in this case I suggest using the URLGenie management pack which gives you the capability to achieve this.
URLGenie Management Pack for SCOM – An Easy, Powerful Solution for Bulk Website Monitoring
https://monitoringguys.com/2015/05/04/urlgenie-management-pack-for-scom-an-easy-powerful-solution-for-bulk-website-monitoring/
----------
(If the reply was helpful please don't forget to upvote or accept as answer, thank you)
Best regards,
Leon