PBP 2023 is scheduled to run between August 20 and 24. The starting town is Rambouillet (view on Google Maps). I've put the approximate route on cycling.routes.fun. This is a massive event, and 8000+ riders are expected to take part. There are also qualifying criteria, and a pre-qualifying period to get your entry in sooner.
The most significant criterion is having to ride a "BRM SR" in the same calendar year as PBP. A BRM SR is a "Super Randonneur" award where all of the rides are classified as "Brevet de Randonneurs Mondiaux" (NOT the same as a regular Brevet de Randonneurs). For confirmation, see these pages on audax.uk: event classification; randonneur awards.
Here are the dates when qualifying BRMs must be ridden:
As far as I can gather, the ability to pre-qualify gives you a bigger choice of start times. The longer your qualifying ride in 2022, the sooner you can pre-qualify. Note that this year is unusual in that it includes London-Edinburgh-London (a 1500km BRM event), so there will be loads of people being able to pre-qualify with a 1000km+ distance.
A UK pubinar is being organised for October, aimed primarily at PBP first-timers. It's at The Compasses in Littley Green near Chelmsford, and there's a thread all about it on yacf. Also in that thread, Lightning Phil has very kindly given an overview of the timescales and what's required to get a place.
There's also lots of information supplied by Cambridge Audax: Cambridge PBP Pubinar #1 ÃÂ¢ÃÂÃÂ The Red Lion, Histon (18 June, 2019).
Here's a useful write-up of PBP 2019.