Trills ?

Is it possible to have a note C that trills with a C#, with the C# (small note) in parenthesis?

The simplest way to do it is to open the Ornament popover (Shift-O) when the C note is selected and then type “tr aug1”. That will create a trill with an augmented unison interval, and will be shown as a parenthesised notehead by default.

Thanks very much Andras !!!