You can input barlines using the bars and barlines popover, both during note input and by adding them to existing music. You can also change the type of existing barlines.
Prerequisite
If you want to input barlines onto single staves only, you have input an independent time signature on those staves.
Procedure
Result
During note input, barlines are input at the caret position.
When you add barlines to existing music, they are added at the rhythmic position of the earliest selected item. They appear to the right of clefs and to the left of other items. If you selected an existing barline, the new barline directly replaces the existing one.
When you add start repeat barlines with a range of items selected, end repeat barlines are also added at the end of the selection.
Surrounding music automatically adjusts to accommodate the barline. For example, note grouping, rests, and tied notes all adjust if necessary. Inputting final barlines at the end of the last bar of flows can automatically trim the flow if there is no further music and depending on the time signature.
Normal barlines that you have input directly, such as to replace an existing double barline, are still considered explicit barlines and break multi-bar rests. Deleting barlines resets them completely.