SQL> create bigfile tablespace users2 datafile '/oradata/ORCL2/users.dbf' size 100M;
SQL> alter database default tablespace users2;
Create new one:
DBCA allows you to choose bigfile tablespace for a Custom Database:
A "General Purpose" or "Data Warehouse" database is actually a pre-created ...
Yes it's possible.
As documented in the manual you can specify a tablespace when creating a table.
However, tablespaces are rarely used in Postgres as they don't really provide any advantage.
One of the few reasons to use them is, when you can't easily expand the size of your filesystem where the data directory is located.