You may either use {{idea}} by itself for the default message or you may add a custom message as an optional parameter.

Template Result
{{idea}} উপায়:
{{idea|Custom message}} Custom message:
Idea

উপায়: I think we could create an {{idea}} template for those who want to propose ideas. --User:Schalice

I agree, this would prove useful. --User:Benzband
I actually think it is pointless, but i wouldn't oppose it as it seems you could make use of it. --User:Example
Right, it seems we're getting somewhere. --User:Schalice
 কৰা হ’ল I created it in it's basic form, but there's still room for improvement :-) --User:Example
অশেষ ধন্যবাদ. -- User:Schalice