I would add that PMF is an investor signal more than a founder one. Basically it says the product is good enough and the company is executing well enough to show extremely strong traction. It’s easy to spot this because the traction is too big to ignore, so any investor paying attention would be immediately interested.

The challenge, is even with this obviousness, it’s hard to run a company searching for PMF. All you can do is continue improving the product, its positioning, marketing, pricing, and so on, looking for strong interest and traction. This is what you’re probably doing already (what else is there), so PMF usually is phrased as a cautionary tale of people who never talk to customers, or never set a price, or never launch, etc. These all will sink your startup for sure, but all PMF will tell you is investors won’t be interested if you have no customers and no traction.