PDF Processing and Barcode Addition

I need to process and print 20,000 single-page PDF records. These PDFs already have names and addresses but require the addition of IMB barcodes.

Requirements:
- Add IMB barcodes to existing PDFs
- Recommend or use suitable software (Design Merge is currently used)

Ideal Skills and Experience:
- Experience with PDF manipulation
- Familiarity with Design Merge or similar software
- Attention to detail and accuracy

Looking for freelancers who can efficiently manage this task.