A drop-down list keeps entries consistent by letting users pick from a fixed set of values instead of typing freely.
Do it with AI insteadSelect the cells
Highlight the cells that should show the drop-down.
Open Data Validation
Go to Data ▸ Data Validation.
Choose List
Set Allow to List, then type values separated by commas or select a range.
Confirm
Click OK — a drop-down arrow now appears in each cell.
Name each sub-list as a range and use INDIRECT() in the second list's source.