I was looking at the docs and came across this, and it said:
CharacterDeath: function (player, killer).

How would I use this? I tried:

OnCharacterDeath(
function(player, killer))
but where would you put the outcome or what happens to the player or killer? To make it so the person who killed the other person got 75 sheild every time I tried:

OnCharacterDeath(
function(player, killer)
player, addsheild = "75")
but it didn't work. It seems that after further studying it applies to everyone when a unit is killed. How would you make it so when a player kills another player(AI or human) they get 75 shield?

A typo...

You said "addsheild" when it SHOULD be "AddShield"...

You need to familiarize yourself with the following before you can even attempt this, as it seems you lack a basic foundation:

[b][color=#FF8000]The FAQ / Everything You Need Thread Version 2.0[/color][/b] wrote:...
LUA
...

• LUA Functions
  ...
• How to use SetProperty/SetClassProperty
  ...
• Trigger animation on destruction of object

...

The last link is good for understanding the structure of similar functions.