I would recommend using Dokka's approval module to approve documents for payment to a new client instead of using old methods such as printing invoices or using mail. There are several benefits to using Dokka's approval module:

1. Time-saving: With Dokka's approval module, you can approve documents for payment quickly and easily, without having to print, sign, and scan physical documents. This can save you and your team valuable time and effort.

2. Transparency: Dokka's approval module allows all parties involved in the approval process to view the document and its status in real time. This transparency can help prevent delays or misunderstandings in the approval process.

3. Audit trail: Dokka's approval module provides an audit trail of all the approvals made on a particular document. This can be helpful in case of disputes or if you need to review the approval history of a document.

4. Centralization: By using Dokka's approval module, you can centralize all your approvals in one place, making it easy to manage and track your payment approvals.

By using Dokka's approval module, you can simplify your approval process, save time, and have a better overview of your payment approvals. This would help you get more done efficiently, and eliminate the need for physical documents, making your process paperless.