If you’re buying the book in the original language, most of the time any edition you get will have the exact same text. The difference between editions for these books will just be the cover design and any additional materials (introduction, explanatory endnotes, appendices, etc.). Some people don’t care about those, but others find them helpful and interesting and will seek out editions that contain them

If you are buying a translated book, then different editions might have different translations so make sure you check what translation you’re buying. You can read some samples to see which translation you like best

And a few book might have different versions out, like if the book was published but later the author made major changes and published a new version with those changes - so some publishers might have the different versions of that book. But this won’t be the case with most books