Managing Word report layouts can be done in the Dynamics NAV application. You use the Report Layout Selection page, which you can find using the search box or in Administration, IT Administration, Reports:
When this window opens, it first loads a list of all the reports available in the application. You can filter the list on the top, as in the following example from Report ID 1306:
You can create or edit a custom layout for the selected report with the Custom Layouts and Run Report buttons.
When I select the Custom ...