Others can speak much better to the Android options, but as far as IFTTT there are already two smart apps in the marketplace section of the smartthings mobile app that greatly expand what you can do it IFTTT and SmartThings.
One allows you to tie a virtual switch to turning on a routine. (Routines were formerly called “hello home phrases.”)
The other allows you to tie a virtual switch to changing a mode. Many people use these with IFTTT.
So if in your particular set up you already have everything working as far as getting IFTTT it’s easy to add triggering a mode or routine.
Open the mobile app, click on the star icon in The lower right to go to the marketplace, choose the smartapps section, choose lights and switches, scroll down to find the switch apps, and install the one you want. (Although the section of the mobile app is called “marketplace” almost everything there, including these two apps, is free. )
and the following topic explains how to set up a virtual switch if you are not yet familiar with those: