@Emmanuella Use Rich content editor → Source mode, add this HTML to your Text Entry question

<link rel="stylesheet" href="https://cdn.jsdelivr.net/npm/flatpickr/dist/flatpickr.min.css">
<script src="https://cdn.jsdelivr.net/npm/flatpickr"></script>
Pick the date and time 3 days from to day. From 09 to 17

Add This Javascript to the same question

Qualtrics.SurveyEngine.addOnload(function() {
    jQuery("#" + this.questionId + " .InputText").flatpickr({
        minDate: new Date().fp_incr(3),
        enableTime: true,
        noCalendar: false,
        dateFormat: "d/m/Y H:i",
        time_24hr: true,
        minTime: "09:00",
        maxTime: "17:00"
    });
});

Qualtrics.SurveyEngine.addOnUnload(function() {
    jQuery('.flatpickr-calendar').remove();
});

Change the time as you wish

For email sendout 3 days after, just make a workflow that send out email and in the setting, put a 3 days delay start

Thank you so much. This worked!

However, the date that is selected from the survey is what I would like to use as the reference to send out the email 3 days after that date. This means that the days emails are sent out would depend on what date users choose in the survey. 

How can this be achieved.

@Emmanuella In that case, the email task in workflow doesn’t support that kind of long schedule. You should use the Webservice task and set-up a schedule distribution with this APIhttps://api.qualtrics.com/573e3f0a94888-create-distribution
You need to change the date to ISO format and add 3 days to it. It will require a code task in the middle and kinda heavy coding.