Hello, water got into the charging port on my e-scooter, but not just light drops. What should I do?

I was recently thinking about buying a 50cc moped and tinkering with it. Maybe adding new parts, personalizing it, wrapping it, and things like that. Just getting to grips with these engines, the technology, etc. To what extent is this legally possible (do you have to register parts, etc.) and how much does it cost?…