Hi Priyanka Awari,
If you Double click the Reference Selector, there will be a Selectable objects tab, there you can select microflow as an option and call your Microflow which returns a list.

See: https://docs.mendix.com/refguide/reference-selector/#293-microflow

You can populate a reference selector using a microflow. In the microflow you can retrieve you data in a list either from the database or with an association to the passed on entity.

You have to return a list at the end of the microflow in order to populate the drop down.

Hi, i am not able to understand your question.

- You said 1-* which means it must be reference-set selector or input reference-set selector

- Because, for 1 -* association I would expect the user to select multiple items

- And you said you wanted a drop down

For 1-*

- use input reference set selector and have a select page, where you could use a microflow

 For 1-1

- user reference selector where it is possible to a microflow

And in your image, it is simple DB retrieval. Which means the same XPATH can be used under selectable objects tab. You could check the constrained by also.