Learn about the Now function in Power Fx. It’s a function that returns the current date and time as a date/time value. It works with the local time of the current user however, while you can use it to perform calculations or comparisons with other date/time values you can use Now to get the current time in UTC by adding the TimeZoneOffset for the given time. The big thing here is that it needs updating, it just keeps the date/time when called, so if you’re on a screen in Power Apps for example, and you call it on screen load, you’re going to have to update it if you’re there for a long time (example shown in this video!).
All demo code is below: