This forum is for people who are using the Samsung smartthings home automation platform. So questions and answers are always in that context.
(It’s a very active forum so it tends to come up near the top Of general home automation Google searches, but it’s not a general forum.)
Assuming you have a smartthings hub, it’s very easy, 
there are literally dozens of battery operated Devices which you can place anywhere in the room. The switch then talks to the hub, and the hub talks to whatever smart bulbs/switches you have set it up to talk to when the battery switch is activated.
All kinds of form factors as well, from ones that look just like a regular switch to multibutton devices.
FAQ: Full list of buttons and remotes confirmed to work with SmartThings
As @Terminal mentioned, as long as you have a smartThings hub, you can also do that with mains-powered smart switches and dumb bulbs.
If you don’t have a smartThings hub, but you use smart bulbs that will work with the Phillips hue bridge, then it also has some “place anywhere“ switches that you can use, although they don’t have as many choices. I think the maximum is four “scenes” from one switch. So it really depends on exactly what you want the setup to be. But certainly you could have one switch that turns on all the smart bulbs in the room at once. And you could put a couple of those in the room, for example if you wanted one at the top of the stairs and one at the bottom. ( The Phillips hue devices are zigbee, by the way, not Wi-Fi. It’s a wireless radio frequency protocol, but a different one than Wi-Fi. That’s why you need to Phillips hue bridge to operate them.)
I don’t know of any similar devices that work with Wi-Fi smart bulbs, though.