Split text into different columns with functions - Microsoft Support
You can use the LEFT, MID, RIGHT, SEARCH, and LEN text functions to manipulate strings of text in your data. For example, you can distribute the first, middle, and last names from a single cell into three separate columns. The key to distributing name components with text functions is the position of each character within a text string.
Add or remove items from a drop-down list - Microsoft Support
If you set up your list source as an Excel table, then all you need to do is add or remove items from the list, and Excel will automatically update any associated drop-downs for you. To add an item, go to the end of the list and type the new item. To remove an item, press Delete.
Remove a drop-down list - Microsoft Support
To remove a drop-down list, click the cell with the list, then click Data > Data Validation, and then on the Settings tab, click Clear All, then OK. A drop-down list is also known as a drop-down box or drop-down menu.
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