How to reconfigure memory

@grimbleshanks - The RAM is 16GB, what is configurable (128GB, 256GB or 512GB is the size of the SSD (nonvolatile storage).

So lets assume you have a 128GB SSD and its becoming a problem as you don’t have enough storage for your work and you’ve already cleaned off as much as you can of old stuff onto an external drive for archival needs.

So what to do?

• You can replace your internal SSD with a larger one! So the first thing is you need to make a full backup of your current SSD as once you take it out you won’t have any means to access what’s on it. I recommend using a fresh drive setup as a TimeMachine backup drive and use TimeMachine to make the backup.
• Next is to order the size you want to go with either going with the custom SSD’s made by Samsung for your system or a 3rd party unit which properly works like OWC or Transcend. For most people a 1TB is more than enough. MacBook Air 13" Early 2017 Blade SSD Upgrade Bundle

Now the fun part!

• If you haven’t already I would recommend setting up a USB Thumb drive as a bootable OS installer downloading the OS installer from here How to get old versions of macOS getting the OS you currently have running on your system if its not the newest version. Then follow this guide How to create a bootable installer for macOS. I prefer this method as Apple internet recovery often messes up on older systems and its faster! Once you’ve got the drive setup plug it in and reboot your system it should boot up under it. If it does then we can take the plunge!
• Now its time to take the drive out following this guide MacBook Air 13" Early 2017 SSD Replacement once done plug in your OS installer and then partition and format your new drive using Disk Utility from the menu and then run the installer proper (I recommend you use a new user ID so its less confusing. At the end of the install it will ask you if you have anything to migrate over and now we need to plug in your external drive and point to it to recover your user accounts and stuff!

Done!