Hello, LiliAF.

I appreciate you in taking the time to do the steps given by my colleague. I'd like to clear some things up about the "Keep custom item information.." option, and address your concern about keeping the description. 

The "Keep custom item information..." option will work if you edited the item's description on the invoice form. QuickBooks will prompt you (depending on the option you selected) if you want to keep this edit when changing the item. 

The option won't work if you want to keep the description (without editing) from the original item and use it on the other one.

So, if you want to keep the description from Item 1 when switching to Item 2, consider copy-pasting the information. 

Need to check your cash flow, financials, and other figures? We have a guide to help you utilize the Reports feature in QuickBooks Desktop: Understand reports.  

Let me know if you have more questions about managing your items in a sales form. Also, feel free to add if you need help with something else like reports or expenses. Always here to help.