Baden-Wurttemberg
As a rule, the respective primary school sends invitations with the school enrollment dates to the parents. If this is not the case, the parents must personally contact the primary school of their residence (https://www.service-bw.de/web/guest/lebenslage/-/lebenslage/Grundschule-5001463-lebenslage-0).
In March / April of each year, parents register their child in a secondary school of their choice. When registering in the secondary school, the registration form, the passport of the child, the confirmation of the primary school about a consultation and the recommendation of the elementary school for a secondary school must be presented (http://km-bw.de/site/pbs-bw-new/get/documents/KULTUS.Dachmandant/KULTUS/KM-Homepage/Publikationen%202015,%202016%20und%202017/2017-07-20-Grundschule-LAY-FINAL.pdf and http://km-bw.de/,Lde/Startseite/Schule/Welche+Schule+fuer+mein+Kind_).