You can save a custom View/Report in Channeltivity by clicking the ellipsis icon in the top right > "Save As."
The "Save View as" window will appear with the below options:
- New View - save a new view with the current fields/columns
- Overwrite Existing View - overwrite a previously saved view with the changes from the current view
How Do I Access Views/Reports That I've Saved?
Once you save a view/report, it will appear in the "Saved Views" section of the lister configuration menu.
How Do I Delete Custom Views/Reports That I've Saved?
To delete an existing view, select "Manage Views" and click the "X" next to the view you want to delete > Save. 
Related Documentation:
- How do I use Dynamic Reporting to create custom reports and Views?
- How do I use Analysis View to Create Custom Chart and Pivot Table Reports?
- How Do I Share a Custom Report/View?