Can I make the message text on an invoice bold type so it stands out more?

Hello Alliedtrailers-g, 

Welcome to the Community page, 

So there is no way of being able to make the message bold you can only make the writing bigger. 

Main cog wheel>custom form styles>click on invoice template> content>click the last box on the right > where it says message to customer on there you can make the writing bigger in that box that is it. Can leave feedback in the main cog wheel.