That part is easy. Use a date picker of some kind

https://developer.mozilla.org/en-US/docs/Web/HTML/Reference/...

or a text field with some code that converts vernacular dates to a structured format. I don't think users are going to be too weirded out at seeing "1997-04-15" and will probably learn to use that natively.

The hard part is that a lot of devs aren't aware that there's a standard and that standard is superior to the alternatives.