Is there a way to upgrade the RAM in an early 2015 MacBook Pro without voiding the warranty? - Quora
How to Upgrade RAM on a 2019 MacBook Pro
16GB Memory Upgrade for MacBook Pro, iMac, and Mac mini
A-Tech 16GB (2x8GB) RAM for Apple MacBook Pro (Early/Late 2011), iMac (Mid 2010 27 inch 4-Core, Mid 2011 21.5/27 inch), Mac Mini (Mid 2011) | DDR3 1333MHz PC3-10600 204-Pin SODIMM Memory Upgrade Kit at Amazon.com
8GB RAM Upgrade for 2011 MacBook Pro & Mac Mini Core i5 & i7 – $34 | OSXDaily
M1 Mac RAM and storage can be upgraded after purchase, but it's not easy - 9to5Mac