Delete WAL archive files

I have around 200Gb of **WAL archives**. Can I just delete them all without considering any database restoration? I am just asking whether it is safe to delete them all or at least 50% of them. I read a book that one must issue pg_basebackup and then delete WAL archives that are older than the "**.backup**" file. But, the postgres manual says that pg_basebackup is for cluster backup. My database is not running on cluster mode. So, is pg_basebackup still relevant for me ? If not, how do I do backup ? I want to implement PITR and may be need something like base backup. I am using Postgres 12. Thanks