The world splits into two main electrical camps: countries running around 220 to 240 volts at 50 hertz, which covers most of Europe, Asia, Africa, and Australia, and countries on roughly 100 to 127 volts at 60 hertz, mainly North and Central America, Japan, and parts of South America. Plug shapes vary even more, with over a dozen socket types in use worldwide.
The key check is printed on your device's power brick or label: if it says something like 100-240V 50/60Hz, it is dual voltage and works anywhere with just a cheap plug adapter. Nearly all phone chargers, laptops, and camera chargers are built this way now. Single-voltage devices, typically anything with a heating element or motor such as hair dryers, kettles, and some grooming tools, need a bulky voltage converter or are simply not worth bringing; buying locally is usually cheaper and safer.
So the practical kit is one or two universal adapters plus a small power strip from home so a single adapter powers everything. Verify your destination's plug type on an official or reputable travel resource before you fly.