The Synod Secretariat
Open is to Your Submissions

Catholics whose dioceses are not conducting an inclusive process are nevertheless able to submit direct input to the synod office in Rome.

Religious communities, lay movements, associations of the faithful, and other ecclesial groups are encouraged to participate in the Synodal Process in the context of the local Churches. However, it is also possible for them, and for any group or individual that does not have an opportunity to do so at the local level [emphasis mine] to contribute directly to the General Secretariat. (page 14 Vademecum)