Put a Persian date in your calendar, on the right day every year
Calendar apps count in Gregorian years, so their yearly repeat is right for a Persian date in most years and wrong in the rest. This works out each year separately and gives you a file to open.
What you will get
Enter a date to see the dates you will get.
Why a plain yearly repeat is not enough
A Persian date is not the same Gregorian day every year. Over ten years from 1405, 20 Mordad falls on 11 August six times and on 10 August four times. Your calendar app can only repeat one of them, so four of those reminders would arrive a day late.
What stays in your browser
The date and the name you type stay in this browser. Nothing is sent anywhere, and there is no link to a calendar service that would carry them in a web address.