Memory Storage

Where can I get access to extra memory for my iMac?

Depends if it is a desktop, go to Scorptec computers is where i purchased 8 x 128GB 3200 speed DDR4 RAMs Corsair vengence LPX, if that helps.

Which model?

iMac (Retina 4K, 21.5-inch, 2019)

If you want absolute peace of mind knowing that it’s the exact right kind of memory then just go here:

according to everymac

So if you are willing to shop around you need to look for PC4-21300 DDR4 SO-DIMM. That is basically smaller form factor memory typically used in laptops. The number defines what speed it is.