Difference between client payment and invoice payment

Difference between client payment and invoice payment

Hello:

During the bank account conciliation I noticed that some payments have the type "Client payment" and another ones have "Invoice payment", what is the difference between this two types?

How I can define to use one or another? 

I recorded all the payments in the same way:
  1. UNCATEGORIZED
  2. Categorize Manually
  3. Category: Customer payment
  4. I select the paid invoices
Thank you!

Ana