Most modern Macs cannot have their RAM upgraded after purchase because the memory is integrated directly into the chip or soldered to the motherboard. iMac (27-inch) Go to product viewer dialog for this item.
: These have slots, though the 2018 model is difficult to access. Old MacBooks : Non-Retina models from 2012 and earlier. Non-upgradable models: All Apple Silicon (M1, M2, M3, M4) : The "Unified Memory" is built into the processor. MacBook Air : No MacBook Air model has ever had user-replaceable RAM. Modern MacBook Pros
Buying more RAM for a Mac is a different experience depending on whether you have an older model or a modern one with Apple Silicon (M-series chips). 1. Check if your Mac is upgradable