PostgreSQL includes one function to generate a UUID:
gen_random_uuid() →uuid
This function returns a version 4 (random) UUID. This is the most commonly used type of UUID and is appropriate for most applications.
The uuid-ossp module provides additional functions that implement other standard algorithms for generating UUIDs.
PostgreSQL also provides the usual comparison operators shown in Table 9.1 for UUIDs.
Read the upstream documentation. For corrections, first check the current version.