Copy DBF files from production to development environment
Do you have an existing database on the development env. and you want to refresh it or is it going to be a new database?  And if this is a new database, do you have the Oracle software installed on the server?

If the database already exists, then the easiest way to refresh is to export the required schema(s) from the production database and import into the dev. database.

I'm providing a very crude example using datapump, but you should follow and read the links @a_horse_with_no_name provided in the comments above:

Export:

expdp system DIRECTORY=your_db_dir DUMPFILE=your_out_file.dmp LOGFILE=your_log_file.log SCHEMAS=schema_a,schema_b CONSISTENT=Y COMPRESSION=ALL


Import (you might need to drop the schemas first or you might need to add the TABLE_EXISTS_ACTION parameter):

impdp system DIRECTORY=your_db_dir DUMPFILE=your_out_file.dmp LOGFILE=your_log_file.log FULL=y


If however you want to refresh the database by copying the DBF files, you have a lot more things to take into consideration.  The very high level steps would be:


Create pfile from spifile from Prod database
Shutdown Production and Development database
Copy DBFs, control files and pfile from primary to development
Do any necessary changes in the pfile to reflect dev. env.
Mount the dev. database using pfile
Change DBF directory names if different from Prod using 'alter database rename file'
Recover database if needed 
Open the database and create spfile


As you can see, this also involves downtime on your production env. and is much more complex.  I would recommend using this approach only if you know what you are doing or with an experienced DBA.  But it would be a good learning experience if you could try this yourself on a separate dev. env. (and if you have enough time and patience to experiment).