user defined memory (UDMs)
 

I am running a case with 4 udfs. I want to store and monitor 3 of the udfs using the UDM function. However the UDMs appear as udm0,udm1 and udm2. How do I change the names of the UDMs and how do I ensure which UDM stands for which udf. Please help!

You can change specified memory number in Define>user-defined>memory...
and also you can change UDM name by the following command,

void Set_User_Memory_Name(int i,char *name)

which "i" is the index of UDM, for example 0 and "name" is what you wish to assign as name to your UDM.
If you desire to load more than one UDF, you may reserve UDM for each one of UDF. Take a look at UDF manual, it has explained things well.

Goodluck