Looking for logging into the Sharepoint Online Page site and are not getting the correct working link for it? In such a case, you can use the links given here by searching your desired login page in the search box. If the page is present on our website then you will get all the links related to the Sharepoint Online Page site. After that you can login as usual with your login credentials.
https://support.office.com/en-us/article/sign-in-to-sharepoint-online-324a89ec-e77b-4475-b64a-13a0c14c45ec
https://www.office.com/?omkt=nl-nl
https://social.technet.microsoft.com/Forums/en-US/d06358ea-0f34-4f21-8517-c9d417371e45/how-to-create-custom-login-page-for-sharepoint-online-office-365?forum=onlineservicessharepoint
https://sharepoint.stackexchange.com/questions/227001/custom-login-page-in-office-365
https://www.sharepointeurope.com/branding-the-office-365-login-page/
https://www.unh.edu/it/kb/article/how-to-login-to-a-sharepoint-online-site.html
https://www.dummies.com/software/microsoft-office/sharepoint/how-to-access-sharepoint-team-sites-in-office-365/
https://www.c-sharpcorner.com/article/how-to-customize-your-own-login-page-or-branding-of-page-in-office-365-online/
http://icansharepoint.com/accessing-sharepoint-online-content-as-an-external-user/
https://www.youtube.com/watch?v=3wQaJyKIhXY
https://www.youtube.com/watch?v=M3mLntGSPxA
https://www.youtube.com/watch?v=bA5nc3CA6cE
https://www.youtube.com/watch?v=6026gAyaoUQ