Newby Questions - Vendors, Customers, and Income vs. Other Income Clarifications

Newby Questions - Vendors, Customers, and Income vs. Other Income Clarifications

Q1.  For Deposits, there does not seem to be an option for "Income".  "Other Income" is an option however.  What is the process to add the option to assign a deposit to type "Income"?

Q2.  In many cases Vendors and Customer are the same.  Vendors may purchase and therefore be Customers.  And visa versa.  The import and export formats for each is different.  What is the method to associate specific Vendors as Customers and Visa Versa?