How to get Date send and date sign ?

How to get Date send and date sign ?

Hi,

Today, when I make a request with Postman, or with cUrl, I can see multiple field with date like created_time... but the value of this field is a number, and I want to know, first if it's possible to get the date of document send, and the date signature of document, and second, how I can convert this number in date.

Thanks you very much,
RB