Most power supply for laptops are universally compatible with the common electrical system e.g. 110V 50 Hz, 110V 60Hz, 220 50Hz, 220 60Hz, etc.
However, the physical plug itself is still different in UK, Germany, US, Thailand, Japan, etc.
So.
1. You will need an adapter for the plug physical form. You can not avoid this.
2. If you will need voltage transformer thingy or not, read those sentences printed or
engraved on your power supply. If it is written 110-240V 50/60Hz, you are good to go and do not need to buy anything in this cathegory.
I travel quite a lot and I have something like this:
https
/www.amazon.de/reiseadapter-Reisestecker-Steckdosen-Stromadapter-Deutschland-2USB/dp/B079QJ6LQQ/ref=sr_1_1_sspa?ie=UTF8&qid=1536303709&sr=8-1-spons&keywords=universal+stromadapter&psc=1
You should be able to find similar stuffs in USA too.