Pedro, As @mayer links to the guide, the tools are listed in there. It’s for a previous model, but tools are likely the very same.
As for adding memory, you probably can’t, as it’s soldered directly to the logic board. SSD should be replaceable, but that’s about it, unfortunately.
Now, opening the device will usually void the warranty provided, but there has been a lot of discussions last couple of years whether it’s legal to deny a warranty just because the user opened the device at home.
Hopefully, when Right to Repair really get’s a foothold, we can have legislation that isn’t so manufacturer-friendly, but allows users to actually do things to their devices, without losing warranties and such