The RSVP addon will do this for you. You can create invitations for the events for all registered users, or by other Joomla user group, or by a custom list, and these users can click through with an attend or not attend status.

How can i try this extension without paying? I see that i have to pay yearly a fee? Is there the possibility of pay just the first year? Any free or cheaper option? This add ons has thousands of options, and in my case, we want sth simplier.

Invitations are only available in RSVP. You only need to pay for one year and then you can use it as long as you wish. If you want updates or support after the year then you need to subscribe again.

I use it constantly at my site for invitations, registrations, payments etc. Works very well.

Hello Borja,

We do offer a 30day money back guarantee too. WE do have tons of options, but that means it can be refined to your usage case :-)

Many thanks
Tony