Dropdowns that support search: The option to be selected can be sent as input and click on the search button. The element is displayed in the dropdown and click enter to select the option.
Dropdowns that support recording of options directly: In this case record the option that must be selected and the same will be selected when the task is executed.
You can also send keys to select the required option from the dropdown using send string or by writing a selenium custom expression in python.