Is there really no Apple Calendar URL?

No. There are webcal:// URLs, but those subscribe to a whole calendar feed rather than adding a single event. For one event, the .ics file is the only route.

Can I use a webcal:// link for a single event?

You can, and it works, but the visitor ends up subscribed to a feed rather than owning a copy of the event. That means they cannot edit it, and it disappears if your feed goes away. Use it for a season of events, not for one.

Why does my .ics file open as plain text?

The server is sending the wrong Content-Type. It must be text/calendar.

Add to Apple Calendar link

Apple never shipped a web URL for adding an event to Apple Calendar, the way Google and Microsoft did. The only route is an iCalendar file. Done properly it is actually the smoothest of the lot: iOS shows a native add-event sheet and no sign-in is involved.

Rather not build the URL by hand? The generator does all of this, including the encoding.

Generate a link

What the file looks like

BEGIN:VCALENDAR
VERSION:2.0
PRODID:-//MakeCalendarLink//EN
BEGIN:VEVENT
UID:9f2c1a@makecalendarlink
DTSTAMP:20260601T090000Z
SUMMARY:Q4 product webinar
DTSTART;TZID=Europe/Brussels:20260910T140000
DTEND;TZID=Europe/Brussels:20260910T150000
DESCRIPTION:A 45 minute session with live Q&A
LOCATION:https://meet.example.com/abc
END:VEVENT
END:VCALENDAR

Three details matter more than they look. Lines end with CRLF, not LF. Lines longer than 75 octets must be folded onto a continuation line starting with a space. And commas, semicolons and backslashes inside text values have to be escaped with a backslash.

Local time or UTC

Use DTSTART;TZID=Europe/Brussels:20260910T140000 rather than converting to UTC. With a TZID the event stays anchored to 14:00 in Brussels, which is what you actually promised people. Convert to UTC instead and the event is still correct today, but if the timezone rules change before the event happens, it moves.

For an all-day event use a date value, with the exclusive end again:

DTSTART;VALUE=DATE:20260910
DTEND;VALUE=DATE:20260913

Serving the file so iOS opens it natively

The headers decide whether iOS shows an add-event sheet or dumps text on the screen:

Content-Type: text/calendar; charset=utf-8
Content-Disposition: attachment; filename="webinar.ics"

Two things to avoid. A data: URI, because iOS Mail and several Android clients refuse to open them, which is why this tool serves the file from a URL instead. And Content-Type: text/plain, which turns the file into a wall of text in the browser.

Reminders

Apple Calendar honours a VALARM block, so you can ship the event with a reminder already set:

BEGIN:VALARM
TRIGGER:-PT30M
ACTION:DISPLAY
DESCRIPTION:Q4 product webinar
END:VALARM

Keep it modest. A reminder the attendee did not ask for is the fastest way to have your event deleted.

One file, many calendars

The same .ics covers Apple Calendar, Outlook desktop, Thunderbird, Proton Calendar, Fastmail and anything else that speaks iCalendar. That makes it the best single fallback if you only have room for one button: label it "Apple Calendar / .ics" and you have covered most of what is not Google.