Look in the articulations & ornaments palette. Select a note and either drag the ornament to it or double click the ornament to place it. If you don't like it's location, such as under the note, then select the ornament and look in the inspector and Change the "Anchor: " location.
If you can't find an ornament change to the advanced palettes by clicking on the word basic at the bottom of the palettes then click Advanced.
If this doesn't help then please clarify your question.
Or maybe you are referring to rhythmic slash notation, in which case see the Handbook under "Tools" to learn how to use Edit / Tools / Toggle Rhythmic Slash Notation.
Comments
Look in the articulations & ornaments palette. Select a note and either drag the ornament to it or double click the ornament to place it. If you don't like it's location, such as under the note, then select the ornament and look in the inspector and Change the "Anchor: " location.
If you can't find an ornament change to the advanced palettes by clicking on the word basic at the bottom of the palettes then click Advanced.
If this doesn't help then please clarify your question.
Or maybe you are referring to rhythmic slash notation, in which case see the Handbook under "Tools" to learn how to use Edit / Tools / Toggle Rhythmic Slash Notation.