This is difficult to answer without knowing one's background. A fun introduction that's sometimes used in Intro to Philosophy courses is Coffee Meets Philosophy by Bruce Waller [0]. It tries to give the reader context in introducing philosophical problems (frankly the most difficult part of understanding philosophy) alongside primary texts. But it is a little weird!

If you prefer to dive into the deep end a bit, the Contemporary Debates series is excellent. For a given area such as epistemology [1], the books contain original essays for and against various positions. These books will give you a good idea what's going on in an area but can be a little dated.

[0] https://www.google.com/books/edition/Coffee_and_Philosophy/b... [1] https://www.wiley.com/en-us/Contemporary+Debates+in+Epistemo...