Preview invite?

Ok, so the Xbox One preview. I know that the participants can send a invite to any of there friends. When a friend invites you, you can register for the preview after a certain verification then you can be invited ( so it is not a guarantee you will get
invited) the Xbox One preview.

So if you have any friends that are participating in the preview you can ask them if they want to invite you.

The Preview programme is by invitation only. If your friends are already in the programme, they can invite you by using the Invite friends page in the Xbox Preview Dashboard app.

As I'm aware of the preview program is already filled and they are not admitting anymore members.

You aren't allowed to ask for preview invites on the forums. A friend can invite you from the preview app on their Xbox.

You need the preview dashboard app to invite friends now, as the preview registration app no longer allows invites.

If you don't have it, you can request it in the preview forums.

You either need to be invited by the team behind the Preview, by way of Live message, or be invited by a friend already in the Preview, at which point you would be sent for review by the Team and then invited by them.