Job Notes were only ever intended to be internal notes and not meant for the customer. They are also a way of communicating information between staff.
Notes intended for customers should either be recorded under the time entries or in the Job Description. These can be made to print on Invoices and Job Sheets etc. (See Settings > Invoice, Quote & Purchase Settings > Invoices Tab > "Use Time Sheet Notes for Line Item Description", also see options under Document Themes)
Another way to add notes on an invoice for the customer, is to add a miscellaneous cost line and then zero out the Quantity value. Tradify treats these lines on an invoice as text lines. These can be positioned where ever needed on the invoice by dragging and dropping them to the desired line position using your mouse.