I need a small but precise TDL extension for Tally (ERP 9 / Prime) that can fill in sales-invoice lines automatically. The flow I have in mind is simple: as soon as I select a stock item, the code should pull the predefined item description (chosen the same way we pick stock items) and write it straight into the invoice without any manual typing. Key points • Works inside the standard Sales Voucher screen. • Reads the item master and inserts the linked descriptive text in the Description field (or another field you suggest if it is cleaner). • Keeps normal Tally behaviour intact so I can still add, delete or edit lines manually when required. Nice-to-have flexibility If the logic you build can later be extended to extras such as barcode scanning, batch/expiry data or multi-unit packs, please structure the code so those hooks are easy to add. You don’t have to implement them now; just keep the framework clean. Acceptance test 1. I load the compiled TDL. 2. I open a Sales Invoice, choose any stock item that already holds a long text description. 3. On tabbing out of the Item column, the description field fills automatically and saves with the voucher. 4. No other standard voucher alters its behaviour. Deliverable • One documented .tdl file (with comments) ready to import, plus a brief note explaining where to attach it in Tally and which object names/fields you referenced. That’s all I need for this first phase; once it runs smoothly we can talk about the email-sending or tax-breakdown extras later.