You can set tablespace status as follows:
Read Write
Users can read and write to the tablespace after it is created. This is the default.
Read Only
If the tablespace is created Read Only, then the tablespace cannot be written to until its status is changed to Read Write. It is unlikely that you would create a Read Only tablespace, but you might change it to that status after you have written data to it that you do not want modified.
Offline
If the tablespace has a status of Offline, then no users can access it. You might change the status of a tablespace to Offline before performing maintenance or recovery on the data files associated with that tablespace.