[General Questions and Answers] lzzat:
Define without USB? Like no OTG USB Storage or no USB cable? If that's the case then you're asking how to root the device without a computer which afaik with Samsung isn't an easy deed (perhaps not possible).

-------------------------------------------------------------------------------------------------

Firstly, you do this at your own risk. Js.

However.. If you can get it up and going on your Mac then try out Heimdall (the Mac/Linux Odin alternative some whiz managed to reverse engineer).

P.S. I have Linux but I've seen Heimdall is available on Mac, unfortunately I can't step you through installation.

https://xdaforums.com/showthread.php?t=2118100

Go to the TWRP.ME site and locate your device and download the latest TWRP image (should be 3.1.1.0)

https://dl.twrp.me/zerofltetmo/

Download dm-verity encryption disabler (without this, it's likely things won't go as planned, it ensures you haven't modified system files etc)

https://androidfilebox.com/miscellaneous/dm-verity-and-forced-encryption-disabler/

Choose a Root method (personally I prefer Magisk but for a first time superuser provider I would recommend SuperSu:

https://download.chainfire.eu/1114/SuperSU/SR1-SuperSU-v2.82-SR1-20170608224931.zip

[ PLACE PHONE IN DOWNLOAD MODE: Hold VOL-DOWN + HOME + LOCK, then press VOL-UP ]

1. Go to Utilities Tab

2. Click Detect Device; if it is not detected you have a problem (find fix then go to Step 3)

3. Output reads Device detected; beneath Download PIT save the file somewhere (e.g. Documents/s6.pit)

4. Go to Flash Tab

5. Beneath Options > PIT, browse for the .pit file you saved in Step 3

6. On the right hand side, beneath Partitions (Files) click > Add, on the left change the partition name to Recovery (where it will ask for a recovery.img file)

--- READ STEPS 7-9 BEFORE YOU DO THEM ---

7. Select the TWRP.img you downloaded earlier

8. Click Start, pick your phone up (be careful not to disconnect it)

9. AS SOON AS THE SCREEN GOES BLACK, HOLD: VOL-

UP

+ HOME + LOCK

--- READ STEPS 7-9 BEFORE YOU DO THEM ---

10. If done correctly (and your bootloader is unlocked, and your RA lock is disabled) you will be in TWRP Recovery. Swipe to allow system modifications (you can always come back here later, you asked for Root so this will suffice).

11. Use Finder (File Browser) to navigate onto the phone from your Mac and copy SuperSU and no-verity onto the Internal Storage

12. From TWRP (on the phone) tap on the Install tab and if you aren't able to see the two .zip files you copied over, you're probably in the / directory; navigate to /sdcard

13. Tap on the no-verity.zip first, continue through, don't worry about using multiple .zips just install and go back when it is complete

14. Tap on the SuperSU.zip. Continue through, same as previous step, this time backing out to the TWRP menu and tap on the Reboot Tab > Choose System

15. If prompted to install anything (TWRP) untick the boxes and tap do not install.

16. Your device should be rooted. Don't turn the phone off, don't panic. SuperSU can cause the first one or so boots to end prematurely and the device will reboot (don't be alarmed if it cuts out).

Note:

On the odd chance that your device is stuck in a bootloop or you are worried about 'bricking' the phone, the only way that can happen (afaik) is if you disconnect during important installations such as during the Odin/Heimdall flash process or TWRP (under certain circumstances, even during Odin/Heimdall you can normally pull through). Otherwise, you'll just end up with a soft-brick (99.9% of the time this is the only thing that happens)

glgl