Sure, it's called a parameter, and you then reference them in the Report->Edit Selection Formula->Record to pass the filter request on to the database, and to get the report to prompt for the value.
If you right click parameters in the Field Explorer and select New, you can define it's type, and then match it to the database type.
To use a month, you can either use a date type parameter and select range, or you can create 2 prompts, one for the month, and one for the year, and then reference them accordingly in your record selection formula.
Examples:
Date range record selection formula:
{table.date} in {?MyDateRangeFormula}
Month year example:
(
month({table.date}) = {?MyMonthParameter}
and
year({table.date}) = {?MyYearParameter}
)
You might also check out my FAQ for more advanced information:
faq767-3825
-k