Macbook Pro 15-inch 2019 butterfly keycap fell off and now I can't clip it back in

If only the key cap itself is damaged, then you can probably buy another key cap to install. However, there are several different versions of these key caps which may have different symbols on them and the black coloring of the key cap itself may differ significantly.

In theory Apple or an AASP should be able to replace just a key cap if the butterfly mechanism itself is undamaged. However, Apple does not make this easy or economical for the AASP since Apple does not sell individual key caps (only an entire set). So the cost to replace one key cap may be more expensive than you may expect although less expensive than replacing the entire Top Case/Keyboard Assembly.

If, however, the butterfly mechanism itself is damaged, then you will need to have Apple or an Apple Authorized Service Provider replace the entire Top Case/Keyboard Assembly which is very expensive. Unfortunately a broken key/key cap is not covered by the free repair program, although it may be covered if the laptop is still under warranty (only Apple can tell you this).

In some regions it is possible to mail the laptop to Apple for the repair. Click the "Get Support" link at the top right of this page to see what repair options are available in your region.

Froot Panch wrote:

I was using my Macbook for work and some gaming when I started to realize that not only did my W key did not work well while I was holding it, but the keycap was also falling off. After closer inspection, I accidentally pulled the keycap off. I watched numerous videos on how to put it back in, but after trying to hook the bottom of the keycap on the clip it just wouldn't stay on, so I'm assuming that the butterfly clip is broken. Since I'm in a lockdown there are no local stores nearby to replace the clip, I can't replace the clip that easily. If there are any solutions that I can buy into, please list them below, thanks :).

P.S, I can still type without the keycap fine, but I believe the clip itself is broken.

[Link Edited by Moderator]

See if you can qualify here: https://support.apple.com/keyboard-service-program-for-mac-notebooks