A slur is a curved line between two or more notes that indicates they are to be played without separation. If you mean to join two notes of the same pitch, see Tie

First Method

1. Leave Note Entry mode and select the first note:
   
2. S creates a slur:
   
3. Shift⇑+→ moves the slur end to the next note:
   
4. X flips the slur direction:
   
5. Esc ends Slur Edit mode:
   

Second Method

1. Leave Note Entry mode and select the first note
2. Ctrl-select (resp. ⌘-select on a Mac) the last note
3. hit S

Adjustments

The boxes or handles (displayed in the images for steps 2-4 above) can be adjusted with the mouse. The two outer handles adjust the start and end of the slur. The two inner handles adjust the contour of the slur.

A slur can span several systems and pages. The start and end of a slur is anchored to a note/chord or rest. If the notes are repositioned due to changes in the layout, stretch or style, the slur also moves and adjusts in size.

This example shows a slur that spans from the bass to the treble clef. Using the mouse, select the first note of the slur, hold down the Ctrl key (resp. ⌘ key on a Mac) and select the last note for the slur, and press S to add the slur.

Note: It is not possible to change the start and end anchor notes using the mouse. Use Shift⇑ + ← or → to adjust the start and end points of a slur.

Dotted line

Dotted slurs are sometimes used in songs where the presence of a slur varies between stanzas. Dotted slurs are also used to indicate an editor's suggestion (as opposed to the composers original markings). To change an existing slur into a dotted slur, right-click on it and choose Slur Properties.... From the Slur Properties dialog, you can choose whether you want a solid or a dotted slur.

X flips the direction of a selected slur.

See also: Tie, Edit mode, Note Entry