you will find in the Tool bar Tab (category) < form >.The button "bar line" you will find in the Tool bar Tab (category) < form >.
Click at the position, at which a new bar line should be inserted. Afterwards, click bar line-insert on corresponding button (Icon).
After inserting of a bar line, two new bars originate with their own time signatures. The time signatures are not shown in this case.
The sense of inserting a bar line makes , for example (this is done occasional on the beginning of songs to get anacrusis), when a repetition-bracket should be inserted within a bar.
The bar-lines are inserted in all voices!