You can set up a default dimension for a specific individual account. The program will then copy this code to the journal, sales or purchase line when the account number field is filled in on the line. However, you may delete or change the code if appropriate.
The following procedure is for setting up default dimension for a customer account.
Open the 
Customer Card
window.
Browse to the specific customer, and then click Customer, Dimensions.
On the new line, fill in the fields. For Help about a specific field, click the field and press F1.
Repeat the procedure for each new default dimension you want to set up.
If an account is going to be used in the Adjust Exchange Rates batch job or the Post Inventory Cost to G/L batch job, do not select Code Mandatory or Same Code. These batch jobs cannot use dimension codes.
Remember that entering a code in the dimension field on the account card does not guarantee that the code will be used when posting because it may be changed on the journal, sales or purchase line. To ensure that the code is not changed when posting, select the Same Code option.
Setting Up Default Dimensions for the Same Account Type
Setting Up Shortcut Dimensions