Use as either singular or plural in meaning but always with a singular verb. That is, always use “the data is” (or another appropriate verb) whether you mean a collection of facts (plural) or information (singular). If you want to emphasize that something is plural, rewrite to use a term such as facts or numbers.
Do not use datum or data are. They are etymologically correct, but some users may not recognize datum, or they may see both datum and data are as pretentious.
The data shows that 95% of the users prefer a graphical interface.
The data gathered so far is incomplete.
These facts contradict the earlier data.
Two words except in product names such as Microsoft® Windows Server™ ...