To show visits from all channels in Reportz, you'll need to create separate widgets for each segment.
First step is to select Custom widget and then customize it as you desire.
Organic traffic sessions
Segment: Organic Traffic
Dimension : Month of the Year (for example)
Metric: Sessions all
Paid traffic sessions
Segment: Paid Traffic
Dimension : Month of the Year (for example)
Metric: Sessions all
Referral traffic sessions
Segment: Referral Traffic
Dimension : Month of the Year (for example)
Metric: Sessions all
Direct traffic sessions
Segment: Direct Traffic
Dimension : Month of the Year (for example)
Metric: Sessions all
Any widget can be further customized. For example, you can choose the Chart style and change the widget title.
The final result on your report should look something like this: