That feature is currently available for hiding individual walls or all objects. Note that it is currently not possible to hide individual objects.
How to Hide a Wall
Tap the wall you want to modify.
A toolbar will appear
Tap Hide.
The selected wall becomes hidden from the view.
How to Show Hidden Walls
Click on Hidden Wall.
Tap on ''Show''
Restore visibility for any wall you want to show again.
How to hide all objects on the plan
Open the project;
Click three dots on the right hand-side;
Open Settings;
You will see the toggle for 'Objects'. Switch it on to show all objects on the plan. Switch it off to hide all the objects on the plan.