There is link between credit management and customer master 
i.e in cmr at sales area level on billing tab page ther is 
field credit control area.we maintain customer crdeit 
information in fd32

In Customer master , we maintain Payment terms whcih 
specify the time period within which the customer has to 
pay his outstanding amount. When the customer is not paying 
within his payment term , he is defaulting his agreement 
and th ecompany needs to govern his credit history more 
closely. To manage this kind of situations SAP has 
developed credit management. This is th elink betn the 
customer master and credit managemnt

we can maintain individual customer credit limit in customer
master in t.code (fd32).we can define the total credit limit
for sales area and credit limit for individual sales area.