PrEP is Pre-Exposure Prophylaxis. It is a regimen you follow to stay HIV-negative. The regimen includes taking medication, getting periodic lab tests, and seeing a healthcare provider. Truvada and Descovy are brand name medications you take as part of the PrEP regimen. Generic versions of both drugs are also available in some countries and are sold under different names.
In addition to medication, PrEP also includes periodic visits with a healthcare provider such as a doctor, physician's assistant, or nurse practitioner, as well as regular lab tests to check your health. The labs include tests for HIV and other STIs like syphilis, gonorrhea, and chlamydia, as well as checking for side effects you may be experiencing from taking the PrEP medication.