The process for receiving CPT varies by school. Generally you apply for CPT through your International Student office. If you are interested in participating in CPT, get in touch with your school advisor to start the process as there are very specific guidelines to follow—for example you must have an employment or placement offer already before getting CPT.
When considering CPT, be mindful of the fact that students who have engaged in 12 months or more of full-time CPT are not eligible for OPT. Watch your CPT hours and days carefully if you would like to remain eligible for OPT!