Xbox insider (Activities) “Friend invite link”

That's not how it works. You can move up in rings based on your activity in the program. Alpha and Alpha Skip-Ahead is by invite only, but those invites are sent by Microsoft. There's no way to ask for an invite. https://support.xbox.com/xbox-one/console/xbox-insider-program

You must be invited to become an Alpha Insider or Alpha Skip Ahead Insider, to do so You must Very active in Xbox, doing missions and report the bugs You see in the system, as much as You do this, so You Will be Very close to become an Alpha Insider. You
must be at least in Delta preview to become an Alpha Insider, but You Just need to be an Insider to be invited to become an Alpha Skip Ahead, but this one is very rare to be invited and there is a certain number of people to be invited, no more than that,
If You were not invited to be Alpha Skip Ahead certain time, so You must wait a Second chance when they Will invite New members.

No one on the forums has the ability to invite you to the alpha ring. You would have to continue being active and wait to see if you get an invite through the Insider hub.

Hi,

Its only with invitation and if you was one of the pioneer of the program.

Now i heard that some new invitation can be send by the staff depending of your activities and rank.

The best advice i can provide you : do all missions inside the insider app.

Regards,

Hi PilotAlbatross

Sorry to hear you weren't able to join the Xbox Preview program at the time of invite. Because that one has now expired, you will need a friend in the program to invite you again.

As for the Windows Insider Program, you can go to
this page which has a link at the bottom to click.

Good luck!

LC