I would like to fill some slots with values (from any source) but before the user prompt any intent. That is, the objective is to inform the user of the values I previously loaded. An example would be: “Hello, I’m Company X’s assistant and I would like to confirm your reservation. I have for {user_name} the master suite on {booking_date} …”
Aside from documentation, there is also the Rasa Masterclass. In addition, we have some examples on github, this is a good example for what you are trying to do.
initial_value is set for a specific slot in the domain file. It will set the slot’s initial value for any instance of the slot.
It sounds like @wvalverde67 wants to set user-specific values (meaning: different for each user/instance of the slot), whereas initial_value is the same for that slot for any conversation. Does that make sense?