The new TWRP 3.0 is available for the Galaxy S6 and other S6 devices like S6 Edge and S6 Edge Plus, for almost all variants of these devices too, but not all builds are available in .tar format which is easily flashable via Odin. You might be looking for .tar format of TWRP 3.0.
Well, there is a simple trick that allows you to install the TWRP 3.0 .img file. You have to use TWRP recovery only for that.
How? So first install the TWRP 2.8.x.x on your Galaxy S6 or S6 Edge or S6 Edge Plus (in fact it works on every Android phone with TWRP version 188.8.131.52 and above). Then download the TWRP 3.0 recovery in .img format, and transfer it to your device.
Next, reboot into recovery mode to access TWRP 2.8.x.x and then tap on Install button. Now, tap on Images.. button at bottom right to direct TWRP to look for and show .img files in place of default .zip files.
Now, browse and select the TWRP 3.0 .img file you transferred to the device earlier, and then perform the swipe action at next screen to install TWRP 3.0. That’s it. Reboot to recovery and you’ll have 3.0 version of TWRP up and running.
So, you need to install TWRP 2.8.x.x first, and then that to install TWRP 3.0. To install TWRP 2.8.x.x, use the following link, as per your device and model no. (see the box for help with model no., or check in Settings > About device).
- International and T-Mobile Galaxy S6 and S6 Edge TWRP 2.8.x.x
- Sprint and US Cellular Galaxy S6 and S6 Edge v2.8.x.x
- Galaxy Edge Plus
→ Download TWRP 3.0 from here (just search for your device and then click on link).