Hi there,
Welcome to the Community. QuickBooks Online enables you to get your work done faster with the help of the powerful features offered in the program. I'll be happy to share more info so you're on the right track with achieving your goals.
The program allows for you to search for data entries using the Advanced Search feature. In order to take advantage of this feature, click on the Magnifying glass at the top right of your account > once the search drop-down appears, click on the blue link that says Advanced Search > on the search filter, select the matching criteria, and specifically filter it to show the line description. After hitting Search, you'll be able to see the entries you're looking for based on the search criteria you use.
I encourage you to try this out and let me know how you make out. I'll be one message away in case you need additional support.