how to send an app request

Allan,
I'm having a hard time understanding exactly what you're looking for, so I'll try to explain both things I think you mention.

If you want to send a request to all users, simply hit the "Send To All Users" button on the page from your image. You'll be given information on how many requests will be sent and be able to verify the information looks correct before sending it.

If you want to allow your guests to send requests to their friends from the front-end of your site, you can:
* Use the JFBCRequests module. Simply install it and publish it on your site where you'd like the button to go. You can create a request with either an image or a simple text link, both options are available easily in the module. The only thing you'll need to know is the Request ID to use, shown in the top right of your image as '1'. Each request you configure has a different ID, and you'll need to use that.
* Use the {JFBCRequest} tag, as shown at the bottom of the image you inserted. You can simply insert that tag anywhere in the front end of your site (in an article, in a Custom HTML module, directly in your template, etc). The exact syntax is right there on that page, so you can simply copy and paste it where you want it to appear.

Hope that helps,
Alex

Allan,
Thanks for clarifying, and sorry for the confusion. There's no way to send a request to your existing Joomla user's to approve their application. To send a request, you must know their Facebook User ID, or be friends with them on Facebook already.

There are restrictions on who can send requests, to prevent spammy behavior. The Request feature to send requests from the admin area can only be sent to users that have already approved your application. This is to prevent applications from simply sending requests/invitations to every user on Facebook. Friends, however, can send requests/invitations to each other even if neither has approved the application first. This is simply because user's shouldn't be spamming their friends.

Hope that all explains and makes sense, but obviously, if you have other questions, just let us know. Additionally, if there was a specific section of one of our guides or other areas that made you think something other than what I mentioned, let me know, and we'll try to clarify it better.

Thanks,
Alex