Normally, once you have created application and provided some deligate permissions in azure ad, you need to accept the Azure AD Consent. wherein in Oauth V1.0 all users when ever the login for the first time to application, they need to accept to access the application. many users feel that it is supicious or unwanted activity. hence it the Oauth V2.0, it has been fixed which is required only one time Consent from the Global administrator of the tenant or application owner to accept on behalf of all users, so that normal users won’t see it.
Administrators can do it using two different options
1. Azure Portal:
Administrator can login to Portal.azure.com–>Enterprise applications –> Permissions and click on Admin Consent and complete the same.
2. Using the Client id and the redirect URL on the browser
simply apse the url with details on the browser and login as Administrator and accept the consent