How can I add another .ibd file to my existing table when the memory space is full? I am working on an enterprise solution on MariaDB. The biggest challenge we are facing is to find a solution if our tablespace is full (.ibd file) and how can we add another .ibd file which will work like a joint memory space. 

Considering we are using file_per_tablespace and MariaDB does not allow any DDM/DDL queries relating to tablespaces and datafiles.
You have the table is full error?

Check you are not out of disk space?

innodb_file_per_tablespace will affect tables newly created.

ALTER TABLE xxx FORCE will cause the table to be recreated in its new tablespace and the old one removed.