Access form to send email automatically that a date is due in 45 days

Hello coders and fellow knowledge seekers. Hope you are well.

I have a form. In this form there is a subform that displays audit dates for each project (All the data in this form are displayed in Single Form View for each project). I am going to input these audit dates manually in their text boxes and they will be stored in a table that has the list of projects and their audit dates, noting that these dates could be changed.

What I need is: a) To add a text box above the audit dates that displays the name of the Next Audit automatically (by comparing the current actual date with whichever next upcoming date I entered in the text boxes of the dates), and highlight the upcoming audit text box if possible. b) To send emails via outlook to multiple people involved in the project notifying them that the next audit is due in 45 days. And I only want the email to be sent once for each audit 45 days prior to its date.

If I enter the dates in date format (dd/mm/yyyy) or sometimes text format (like 06-Jan-2001). Will the code still be able to comprehend, or it is better if I unify my date entry to one format?

I am relatively new to coding, so I would really benefit from a thorough answer :) I have attached pictures for further demonstrationdemonstrative picture. Thank you for your efforts.