Use slicer to filter every sheets

You can do this by putting a filter at the report level

If you really want to use a slicer, go to View > Show Panes > Sync slicers

Select the slicer you want and you can change which pages it filters and/or shows up on

Hi Bebs ,

Thanks for the reply from Syk , please allow me to provide another insight:

Open the Sync slicers pane by going to the View tab in the ribbon and checking the "Sync slicers" option.

This will open a pane on the right side of your Power BI Desktop window.

In the Sync slicers pane, you will see a list of all your report pages.

For the slicer you want to sync, check the boxes under the "Sync" column for each page you want the slicer to affect.

You can also choose to make the slicer visible on each page by checking the boxes under the "Visible" column.

For more details on using slicers, including synchronizing slicers across pages, you can refer to the official documentation here:

Slicers in Power BI - Power BI | Microsoft Learn

If you have any further questions please feel free to contact me.

Best Regards,
Yang
Community Support Team

If there is any post helps, then please consider Accept it as the solution  to help the other members find it more quickly.
If I misunderstand your needs or you still have problems on it, please feel free to let us know. Thanks a lot!

Thanks both of you.

My plan was to mainly use the filter panel AND to create a sheet dedicated to selections to help people to initialize their selections. 
I tried to use Slicers Synchronization, My concern is : If slicers are not displayed on a sheet, you don't see selections anywhere ? (not even in the filter panel) ?Is that is ?