NOW
Applies to: 
Calculated column
Calculated table
Measure
Visual calculation
Returns the current date and time in datetime format.
The NOW function is useful when you need to display the current date and time on a worksheet or calculate a value based on the current date and time, and have that value updated each time you open the worksheet.
Syntax
NOW()
Return value
A date (datetime).
Remarks
The result of the NOW function changes only when the column that contains the formula is refreshed. It is not updated continuously.
In the Power BI Service, the result of the NOW function is always in the UTC timezone.
The TODAY function returns the same date but is not precise with regard to time; the time returned is always 12:00:00 AM and only the date is updated.
Example
The following example returns the current date and time plus 3.5 days:
= NOW()+3.5