populate one fields with two fields

Hello Team,

I would like to combine values of two fields on a page to one text field. Following is the demonstration:

On Customer form,

Month (Data Type: Option (January, February,...))

Year (Data Type: Option(2018,2019,2020,2021,...))

Intake (Data Type: Text(30))

The formula of "Intake" should be (Month,"/",Year). 

Kindly assist on this.