What is a picklist?

How to create a picklist?

1. Select the cell/cell range in which you wish to insert the picklist.
   
2. Navigate to Insert > Picklist > Create Picklist. Alternatively, you can select from the predefined list of picklists.
   
3. From the side pane that appears, you can either select Single-Select or Multi-Select.
   
4. Select how you wish to display the values—List or Cell Range.
   
5. Enable Display as chip if you wish to display the values as chips/bubbles inside the cell.
   
6. Select the preferred colors for the values in the picklist with color options drop-down.
   
7. Once you're done, click Create.

You can not enter any other values manually. If you want to enter a value that is not in the list, you will have to edit the existing drop down list and add the value you want.

How to edit an existing Picklist?

1. Navigate to Insert > Picklist > Manage Picklist.
   
2. From the side pane, click  to edit the preferred picklist. Alternatively, you can also edit the picklist from the drop-down. 
   
3. Remove/add values to the list as you desire, and click on the Save button.

Editing a value from the picklist will effectively change the old value to the new one, in every occurrence until then. This saves you time and effort, and you'll not have to change it manually in every othere place!

How to use a picklist in another range?