You can sign into your Tesla account online and download a copy of the manual for reference reading on your laptop or phone. I have it on both of my devices out of convenience. Click the "Manage" button below your car's VIN, in the next window you'll see "Download Owner's Manual" on the bottom right. It's in searchable .PDF format.
As someone mentioned you can also conveniently find a copy on your car's screen by clicking on the Tesla "T", and locating the "Manual" link at the bottom.
The Owner's Manual does periodically get updated as new features or changes get made so periodically check back. When your car gets an update you'll see Release Notes on your screen that you can read through before driving, and eventually the info will be incorporated into the next Manual update.