In the help of Qlikview you can find some information of what you need. Here you have the link of these three functions:
Match() is used for a case sensitive comparison. It matches the exact searchstring you pass in the function.
for Example: Match(Name,'Vivek') , returns true if a person's name is exactly Vivek (V caps).
WildMatch is used for a match where a string can be part of the search string.
For example :Match(Name,'Vivek') will return true if a person's name is Vivek, Vivekanand or some other string containing Vivek in it.
MixMatch is same as Match but it is case insensitive.