In order to make an object public, click on Visibility in the drop-down menu, set it to Public and save the setting.

If you upload a file by using the CLI, you can make it public by using the parameter: --acl public-read

Note: You can only configure the visibility (public or private) of one object at a time. It is not possible to perform this action on an entire bucket, on which visibility is defined by default as private. Allowing public visibility on a bucket only allows the viewing of a list of objects that are stored in the bucket.