I just noticed that my Purchase Order Template which is in my current company file does have the lines (see attached). That means that my company file has no issues or glitches in general. Could it be that it is the individual format of the Invoices and Estimates that needs to be adjusted?

I viewed the printer setup for the three of them (Estimates, Invoices & Purchase Orders) and it was the same for all three. I don't know why the lines are only shown on the Purchase Order template.

I thought it had to do with customization of the templates but I transferred the Estimate Template from the new company file which has the lines to my current company file, opened it in the Estimates formate and it still didn't work.

I hope this updated information can help on finding the a solution.