To select the series and load purchase vouchers in Buk voucher creation / modification option, you need to follow these steps:
Step 1: Open your company then go to Administration.
Step 2: Select Bulk Updations and click on Bulk Voucher Creation / Modification.
Step 3: Select the voucher type such as Sales, Purchase, etc then click on Configure button.
Step 4: Here, you need to Add Format and configure all the fields used in the voucher.
Step 5: Now, select the format you have created and press F2.
Step 6: Here, select the Vch Series and date range then click on Load Vouchers.
Note: Take backup of your data before making any changes.