Thanks for posting your request.
Since your Product titles are pulled from the Item names in your Product Catalog, if you edit your Product/Item names there, using the step-by-step instructions in the link below, those should sync over to your Packing Slips.
To include unique messaging based on specific if/then criteria, we would recommend creating multiple Packing Slip templates, and use Shipping Rules to assign those to your orders. The links below may help as a springboard for setting those up.
- Best of Rules: Assign unique packing slips to orders per store
- How to: Design a custom Packing Slip Template
- FAQs: Shipping Rules / Mapping
- What Shipping Rules are available for set-up?
I hope that information helps, but if you have further specific use case information regarding the line breaks you need to make based on characters in your Product Names, please let us know.