Create Dropdowns in Excel
You can create a dropdown using the Data Validation in Excel .
Goto Data Tab -> Data Validation
In the Source you can enter =OFFSET($D$3,1,0,COUNTA($D$4:$D$12),1) , The $D$3 acts as the starting point, Counta provides the name the total count of values entered from D4:D12 , so any new value entered is picked up automatically .
Hope this helps
Happy Learning