Once you create a drop-down list, you can use App Script to modify the list to allow for multiple selections. If you want to save time: Make a copy of my template.

And, if you enter data in the Google Sheets mobile app on Android or iOS, does a drop-down list make data entry faster and more efficient?

It's easy to add a drop-down list in your Google Sheets in order to sort and organize data. Here's how to do it.

How to add scripts to Google apps If you’re comfortable with JavaScript, you can write your own original programs. Just open Docs or Sheets and go to Extensions, then click on Apps Script.

Learn how to change the drop-down options in Google Sheets, edit list items manually, or change the contents of a range of cells.