On the Teller Deposits/Withdrawals screen, you can use one of the following Process Codes (enter the code into the far-right "Proc Code" column next to the loan account):
 
L - Use this code to post the ENTIRE deposit amount to principal
 
X - Use this code to override the default payment matrix and specify exactly how the payment amount should be distributed between principal, interest, escrow, fine, etc.   
 

For more details, click on the links below to open related online help topics.

NOTE: For Mortgage loans that use the 360-day interest calculation type, if you put a deposit amount that is different from the normal scheduled payment amount (plus escrow, if any), the system will automatically pop a window to allow you to specify that the entire amount (or extra, if the deposit is larger than a normal payment) will go to principal only.