"Personal information" is information about you such as your phone number, address, age, photos, bank account number, and so on. People usually want to keep their personal information secret.
"Information" is one of the most common words to use together with "personal". Other common combinations are:
- in my personal experience (use this when talking about things you've learned in the past)
- have a personal life (the things that you do which aren't related to work)