Long story short, I underperformed at work and failed a bunch of exams Employed for 6 months Grad scheme Invited to a capability meeting If I am put on PIP, will my next employer find out I was on PIP? Based on the UK
It's unlikely that they would put it directly in a reference as this is (most likely) a violations of privacy or confidentiality laws and would be a minor legal exposure risk. See for example: https://www.refapp.com/blog/unveiling-the-legal-landscape-of-reference-checking-answers-to-common-questions
It's however possible that it would show up "in code" in the reference especially if the prospective employer asks about it.
There is always the "unofficial" path as well. The hiring managers knows someone who knows someone and the topic my come up at a casual phone call or when going out of for after work beers in a pub.
In the USA putting anything in the reference other than “X worked here from this date to that date” puts the company at risk of getting sued. Maybe not successfully, but being sued is always a cost they want to avoid. If you were fired for raping another employee and there is evidence of that, then it is very likely that this goes into your reference.
In other countries the chances of being sued are usually less, but it’s still a risk.
If you are planning on failing the PIP, may I submit that worrying about outcomes you can't control isn't really useful.
The alternative is you take control of the situation and survive the PIP, or fix your problems before the PIP starts. Or voluntarily resign before failing the PIP.
See past answers about PIPs.