In the "Administrative Areas" section in the map tools, click on the closed eye icon next to the administrative area you want to see

Note: if this "administrative areas" is not in your project, you might be in a country where they are not available yet. Please get in touch so we can help you.

You can display several administrative areas at the same time

Postcodes and city boundaries are the most common ones.

To hide them all, click on the eye next to "Administrative areas"

And the administrative areas will be hidden as a consequence.

Visualise postcodes and other administrative areas