1. Know the basics: An invoice is a document sent to your customer that includes details about the products or services provided, the total amount due, payment terms and instructions.

2. Create a professional layout: Design your invoice with consistent branding, colors, and fonts. Ensure it is clean, clear, and easy-to-read.

3. Include your company information: Display your company name, address, phone number, email address, and website prominently on the invoice.

4. Assign unique invoice numbers: Create a unique invoice number for each transaction to help with tracking and organization.

5. Include your client’s information: Clearly list your client’s name, billing address, email address or fax number (if applicable).

6. Specify a clear due date: Indicate a specific due date for payment to avoid any confusion or delays.

7. List products or services provided: Include detailed descriptions of each item sold or service performed, along with the quantity, unit price, and line total.

8. Calculate the subtotal: Sum up the individual costs of all items or services listed on your invoice.

9. Apply discounts or promotions (if applicable): Deduct any discounts or promotional offers promised to your customer.

10. Include sales tax (if applicable): Determine and add the required sales tax based on the location of sale and your local regulations.

11. Calculate the total amount due: Add up the subtotal, discounts (if any), and taxes to determine the final total amount that your client needs to pay.

12. Clearly outline payment terms: Specify acceptable payment methods (e.g., credit card, check), any late fees or interest for overdue payments, and any early payment incentives if applicable.

13. Add payment instructions: Provide detailed instructions on how customers can make a payment such as mailing address for checks, online portals for credit cards and bank transfers.

14. Attach supporting documents (if necessary): Include any necessary supporting documents, such as contracts, receipts, or purchase orders, as attachments with the invoice.

Following these 14 steps will not only help you create professional and clear invoices for your customers, but also improve your record-keeping and streamline the payment process for a better customer experience.