Question: I would like to be able to play a piano or keyboard and have what I play stored and reproduced as musical notation. Is that possible?

Answer: 
Any keyboard that is MIDI capable can be plugged into a computer running notation software.

Although we don't offer recommendations for specific products here, just know that most electronic keyboards support MIDI, and most notation software supports converting what you play into sheet music.
Many MIDI keyboards have built-in recording and playback facilities, for example [this one](https://www.argos.co.uk/product/7834781). Back in the day when PCs were still desk-size monsters and mobile phones only made phone calls, this was the main way you got to record what you played.

These days though, most manufacturers are actually taking that feature out. No-one needs it these days because everyone has a phone or PC they can connect instead, and your phone or PC has way more recording capacity than anything that would be built into the keyboard.

So a far better approach as a beginner is to find a keyboard which plugs into whatever device you're going to be using, and get some software to do the recording. Almost every keyboard these days will come with a bundle of stuff to do that, which will get you started.