Is there a way to enter con bocca chiusa for a choral part?
In Dorico terminology, this is a Playing Technique and would be found in the Choral section of the Playing Techniques panel, on the right side of Write mode. However, this particular playing technique does not currently exist (there is a symbol for Mouth Closed, though, in case you find this useful).
Currently, you cannot create your own custom Playing Techniques, but this is apparently planned for an update.
For now, you can create text using Shift-X.
Thank you for your reply!