Hi Vinicius Perpetuo,

First of all , you have to enclose that button or whatever u dont want to print in a container like this:

Second , open CSS editor which is present on top beside theme editor and apply css like this:

@media print

 {

 .printbtn{ 

       visibility: hidden;

}

}

 Third, you have to apply that class on that container in which you enclose that button which you dont want to print like this:

lastly, publish and check

That's all !!!

Hope this helps you !!!!!

Regards

Reemali