Before you proceed, you need Spaces installed on your phone.
How to change the privacy/visibility of a Space?
Step 1 - Open the Space for which you want to change the privacy.
Step 2 - Click on the three-lined icon located on the top right corner of the screen.
Step 3 - SelectSettings.
Step 4 - Under the Privacy section, select the one based on your requirement - Private/Semi-Private/Public. When you are done, click on the right tick button located on the top right corner.
*You can change the privacy setting only within 24 hours of the creation of the Space.
You are done!