Jackietools :
You are telling me I can remove the 500 go, install the 1 TB and just reinstall High Sierra? Wouldn’t I need the USB bootable thumb drive to do this?
Macs use internet recovery. According to Apple. If you've ever installed 10.12.4 or later. If you boot a Mac using Option-Command-R it will load the installer for the latest compatible version of macOS for that Mac from the internet. I've done internet recovery several times on client computers and it's worked fine. Although it's been for purposes of a repair install in my uses.
Your current Mac also has a recovery partition. Don't let the name fool you. This contains a full vanilla installer of the macOS you have installed. So, you don't even need the Internet. Just hold the "option" key when you boot and select "Recovery HD". This will load you into the macOS recovery partition. From there you can wipe the new SSD if it is plugged into a USB or Thunderbolt enclosure using Disk Utility. Then quit Disk Utility and select Reinstall to install macOS. As long as you select the new SSD it will perform a clean install of macOS exactly the same as if you used internet recovery, DVD or USB flash drives.
In some ways macOS is not as finicky about installs as Windows. It doesn't matter if you set it up first as a USB drive. Just unplug it and install it internally. It will boot just the same. You could even install it on another Mac of a completely different model and generation, unplug it and plug it into another Mac and boot. The OS is pretty portable.
I haven't tested the scenario of removing a drive and installing the latest via recovery though. As I keep an installer USB Flash drive partitioned with all the major Intel versions of OS X with model cut offs. Since it is faster than internet recovery and they may have a slow connection.