The Azure AD B2C login screen can be customized to suit our branding. Refer Customizing the UI
Refer https://github.com/NewtonJoshua/Azure-ADB2C-Angularjs-sample
In this sample we have two customized UI screens,
In adCustomPages/unified.html, at line 442 and 445, enter your tenantName, password-reset-policy and clientId
The pages should be uploaded in a blob and their url should be referred in the Azure AD B2C policies.
Now in your application you can see the customized UI.