How to run a bill with a Trust Account

Make sure the firm is set up as a billing vendor (File > Setup > Vendors).
In Abacus Accounting, go to Billing > Print Bills and click Add in the upper-right. It is usually best to work in the middle tab, Select Bills Individually.
Select the appropriate Matter and fill in the correct information. Note the Trust on Bill area in the lower-right and make the appropriate selection for this bill.
Click Add to Billing Run.
Select the bill, choose Preview under Destination, and click Preview. Note the trust information on the bottom of the bill.
Close the bill.
Go to Billing > Post Bills
Highlight the bill that you just printed and note the Vendor # area on the bottom of the window; this is the vendor that will be the Payee on the trust check and should be the firm if it is set up as the billing vendor.
Post the bill
Click Done to close the window and then go to Trust > Print Trust Checks, Check Selection tab.
Highlight the trust check and click Print
The next page will allow you to change the check number and the option to Post Only (e.g., online bank transfer). Click Post (or Print if you opted to print a physical check).
Click Cancel to close the window.
Go to Billing > Payments Received
Highlight the check that you just printed and click Post. Abacus Accounting will automatically reference this payment for the appropriate invoice and update the matter billing ledger.
Click Done to close the window.