I think I got it now. Use the operators I mentioned. If the dates have no time value (e.g. you used Date() function to insert a date rather than using Now() )
then you one one of the following, depending on the desired range (e.g. January 1, 2019 and September 30, 2019)
BETWEEN #01/01/2019# AND #09/30/2019#
>= #01/01/2019# AND <= #09/30/2019#
or to have a parameter prompt
BETWEEN [Enter Start Date] AND [Enter End Date]
>= [Enter Start Date] AND <= [Enter End Date]
You can also use form fields for date values. That and the parameter prompts have some drawbacks, such as the fact that you can pass anything or nothing and the query will still run.
EDIT -
"[startdate] and [enddate]"
the quotes will raise an error...
The more we hear silence, the more we begin to think about our value in this universe.
Paraphrase of Professor Brian Cox.