In most IT systems, the term credentials, also refered to as creds, refers to the combination of your user name and password you use to log in to the system in question. This is true for SharePoint, Office 365, Outlook (and Exchange), all of which generally use Active Directory to confirm you are who you say you are when you log in with your credentials.
More generally, a credential is an attestation of qualification, competence, or authority issued to an individual by a third party with a relevant or de facto authority or assumed competence to do so.
Examples of credentials include academic diplomas, academic degrees, certifications, security clearances, identification documents, badges, passwords, user names, keys, powers of attorney, and so on. Sometimes publications, such as scientific papers or books, may be viewed as similar to credentials by some people, especially if the publication was peer reviewed or made in a well-known journal or reputable publisher.
Information systems commonly use credentials to control access to information or other resources. The classic combination of a user's account number or name and a secret password is a widely used example of IT credentials. An increasing number of information systems use other forms of documentation of credentials, such as biometrics (fingerprints, voice recognition, retinal scans), X.509, public key certificates, and so on.<ref>Content used under Creative Commons license from Wikipedia. See source for more details.