These are the notes I saved for myself.
I believe there are also some 3rd party drivers available as an alternative. Most of these (or maybe all?) are not free. All of them have the look of the kind of suspicious stuff aimed at Windows users.
The best advice would be to avoid dodgy old disk formats like this. There's probably good reason it's write disabled by default by the OS. I believe I've seen a driver install included with external drives before as part of the included (and already written to the drive out of the box) software. I always completely erase and reformat any new drives myself as SOP. Avoids problems.
Anyway, those notes:
1. On your Apple computer, connect an NFTS-formatted drive to an external port. Take note of the volume name, as you'll need it later.
2. Launch Terminal.app and type in the following command, entering the admin password when prompted
sudo nano /etc/fstab
3. This will open the fstab file that is blank by default. Now, using the volume name, enter the following command
LABEL=VOLUME_NAME none ntfs rw,auto,nobrowse
4. Press [Ctrl]+[O] to write the information to file, then press Enter to save the change
5. Repeat steps 2-3 for each drive you wish to enable NTFS write support on, and then press [Ctrl]+[X] to close the file
1. Next, eject the drive(s) and mount them again. This time, you'll notice the drive does not appear in the Finder. Select Go | Go to Folder... from the Finder menu, enter /Volumes, then press Enter to view the hidden volumes connected to your Mac. From here, you'll be able to drag and drop the volume(s) to the sidebar for easy access when reading and writing to/from, as it does not mount on the desktop unfortunately.
To undo the edits made to the etc/fstab file, simply load the file (as in step 2) and delete the entries created for each drive, then save and exit. That's it!
While this is quick and easy to implement, it's not without drawbacks, such as occasional instability, the fact that it's unsupported, and you can only enable it on a per-drive basis. If you manage multiple drives, need this to work quickly and efficiently, or if you're deploying this as a solution to multiple end users, then a more robust driver like those provided by 3rd-party developers (such as FUSE or Tuxera) might be a better solution for production or mission-critical needs.