I assume you meant 433 MHz, since that’s what your topic title said?
If so, SmartThings does not have that frequency radio inside of it, so you are not going to get direct integration.
There are a number of community members who have created integrations using an additional device as a “man in the middle.”
It depends in part on what you are trying to control.
If it happens to be a fan that has a 433 MHz remote, there is a new device, the bond, which can generate a 433 MHz signal for fans and has an IFTTT channel, so you can get limited integration that way. But at $99 it’s expensive and it can only issue a limited set of commands.
I think most people use the Broadlink RM. it costs less and can work with more devices, although you will also need an android device as a go-between. And it’s a fairly complex set up.
And some people have used an arduino with a 433 MHz transmitter.
Just search the forums for “433” and you will find a number of discussion threads on various options.