In Dynamics CRM 2016, an attribute could be of the following data types:
- Single line of text: This is a string representation, for example, a name.
- Option set: This is an attribute that can have values in a picklist, for example, a title can have possible values of Mr., Mrs., and Miss.
- Two options: This is an attribute that can have only two possible values.
- Image: This is an attribute to which we can upload some image.
- Whole number: This is an attribute that can acquire an integer value.
- Floating point number: This attribute can assume a float value. It is similar to a decimal and is generally used when we are not much concerned with accuracy after the decimal point.
- Decimal number: This attribute can assume a decimal value.
- Currency: This attribute can assume money-related value. For example, we can create an attribute for representing a salary of 100 dollars per day. The dollar component, that is, the currency component will be saved in a base attribute. The base attribute is created automatically when a currency attribute is created. The value component, that is, 100, will be saved separately from the base component.
- Multiple line of text: This is a multi-line string representation, for example, the description of a book.
- Date and Time: This attribute can assume a date-time value, such as the date of a class.
- Lookup: This attribute links two different entities.
- Customer: This attribute links the entity to an account or a customer.
For a detailed explanation, you can refer to this MSDN link:
https://msdn.microsoft.com/en-in/library/dn817862.aspx
https://msdn.microsoft.com/en-in/library/dn817862.aspx