Following scripts will backup the tablespace and datafile present in Oracle Database.

First you need to list the schema with RMAN Report:

RMAN> report schema;

Report of database schema for database with db_unique_name XE

List of Permanent Datafiles
===========================
File Size(MB) Tablespace           RB segs Datafile Name
---- -------- -------------------- ------- ------------------------
1    910      SYSTEM               YES     C:\ORACLE\ORADATA\XE\SYSTEM01.DBF
3    660      SYSAUX               NO      C:\ORACLE\ORADATA\XE\SYSAUX01.DBF
4    65       UNDOTBS1             YES     C:\ORACLE\ORADATA\XE\UNDOTBS01.DBF
5    250      PDB$SEED:SYSTEM      NO      C:\ORACLE\ORADATA\XE\PDBSEED\SYSTEM01.DBF
6    370      PDB$SEED:SYSAUX      NO      C:\ORACLE\ORADATA\XE\PDBSEED\SYSAUX01.DBF
7    5        USERS                NO      C:\ORACLE\ORADATA\XE\USERS01.DBF
8    100      PDB$SEED:UNDOTBS1    NO      C:\ORACLE\ORADATA\XE\PDBSEED\UNDOTBS01.DBF
13   260      PDB1:SYSTEM          NO      C:\ORACLE\ORADATA\XE\PDB1\SYSTEM01.DBF
14   400      PDB1:SYSAUX          NO      C:\ORACLE\ORADATA\XE\PDB1\SYSAUX01.DBF
15   100      PDB1:UNDOTBS1        NO      C:\ORACLE\ORADATA\XE\PDB1\UNDOTBS01.DBF
16   5        PDB1:USERS           NO      C:\ORACLE\ORADATA\XE\PDB1\USERS01.DBF

List of Temporary Files
=======================
File Size(MB) Tablespace           Maxsize(MB) Tempfile Name
---- -------- -------------------- ----------- --------------------
1    129      TEMP                 32767       C:\ORACLE\ORADATA\XE\TEMP01.DBF
2    62       PDB$SEED:TEMP        32767       C:\ORACLE\ORADATA\XE\PDBSEED\TEMP012019-09-18_15-38-03-475-PM.DBF
4    62       PDB1:TEMP            62          C:\ORACLE\ORADATA\XE\PDB1\TEMP012019-09-18_15-38-03-475-PM.DBF

RMAN Backup script for the tablespace

run
{ 
allocate channel c1 type disk format 'C:\archive\backup\%I-%Y%M%D-%U' maxpiecesize 5G;
allocate channel c2 type disk format 'C:\archive\backup\%I-%Y%M%D-%U' maxpiecesize 5G;
backup tablespace PDB1:USERS, USERS;
release channel c1 ;
release channel c2 ;
}

RMAN backup script for the datafiles

run
{ 
allocate channel c1 type disk format 'C:\archive\backup\%I-%Y%M%D-%U' maxpiecesize 5G;
allocate channel c2 type disk format 'C:\archive\backup\%I-%Y%M%D-%U' maxpiecesize 5G;
backup datafile 7,16;
release channel c1 ;
release channel c2 ;
}