Hi @Anonymous,
Could you please share a bit more about your scenario?
Do you want to send an reminder notification to a user based on date within PowerApps?
If you want to send an reminder notification to a user based on date within PowerApps, I afraid that there is no direct way to achieve your needs in PowerApps currently.
I agree with @Jeff_Thorpe's thought almost, you could consider take a try to create a flow (Microsoft Flow) to achieve your needs.
I assume that the Due Date of your trip is 08/03/2018, and you want to send an reminder notification to you every day. I have made a test on my side, please take a try with the following workaround:
Within Condition box, click "Edit in advanced mode", type the following formula:
@lessOrEquals(formatDateTime(utcNow(), 'MM/dd/yyyy'), formatDateTime('2018-08-03T00:00:00Z', 'MM/dd/yyyy'))
More details about sending an email reminder using Microsoft Flow, please check the following video:
https://www.youtube.com/watch?v=YNkWEIddWDc
Please also check if the following blod would help in your scenario:
https://flow.microsoft.com/en-us/blog/fotw-remind-to-post/
More details about Microsoft Flow, please check the following article:
https://docs.microsoft.com/en-us/flow/getting-started
Best regards,
Kris