This custom recovery is compatible with all Samsung Galaxy S6 versions including T-Mobile and ATT one. To install custom recovery without rooting your device, you must have ODIN on your computer. Then download the tar file from bottom of this post and power off your Samsung Galaxy S6.
Put the S6 into download mode by pressing and holding power button and volume down button and then connect it to your PC. Then use the PDA button to browse the TAR file you downloaded earlier and click on the Start button to flash the custom recovery into the Samsung Galaxy S6.
This will install TWRP into your phone that supports touchscreen input as well. Onscreen keyboard input is also supported which is other wise not supported in CWM.