How to pass SSO(Single Sign On) when calling a page

Problem:
I'm a user of APImetrics. When I use api call to visit a page which is protected by SSO. Everyone who wants to log in URL will be redirected to SSO page.
Once account's userid and password are authorizated rightly. URL displays. I read many times office documents and tried many ways. But nothing is works.
I have no idea to find a solution how to get a authorization to pass SSO.
Please help me to solve this problem.