How can I get NOW (Date and Time) and Show in my form without field in database?

function, Script ?

I try with

"Conditions" -> "update/calculate field" -> "Do" -> not Now function to select?

Let me see if I understand what you need:

1. You want to display the default time and date on your form now() - right?

2. I'm not sure what you mean by you don't want the field in the database - 

Perhaps I don't have all the information - but I don't think you can use conditional logic because it works with fields -which submit values to your form's database. 

A simpler method would be to use the date-time field:

Let us know if this helps