InfoPath: How apply formatting rule of a date field?

Add the 'Date' field to the form, and change the control to 'Text Box'

SPServices : How to prepare date data for the SharePoint list date field using JavaScript?

var currDate = new Date();

var numDay=currDate.getDate();
var numMonth = currDate.getMonth();
var numYear = currDate.getFullYear();

var tempDate = (++numMonth)+"/"+(numDay)+"/"+numYear ;
var spDate = new Date(tempDate).toISOString();

//e.g. 2019-08-29T18:30:00.000Z


Note: You may have to adjust numDay based on the timezone.