By default, booth sizes are shown for all available booths and those "On Hold" (however, not for the sold ones).

If you don't want your exhibitors or attendees to see booth sizes (for example, during virtual events), you can hide them on the floor plan.

Go to Settings - Floor plan and scroll to the "What booth info to show" section. You will find the Hide booth size checkbox.

After you check this box, booth sizes will be invisible on the live plan, but you will still be able to see them in the Designer  and booth list.

The sizes can't be hidden for a specific booth, only for all.

The booth sizes and the booth names/exhibitors' names in booths will be automatically adjusted depending on how zoomed in or zoomed out the view is.