A trend line follows a trend – do you mean a horizontal line? If so then the Donchian Channel indicator is the one you want and it is a standard indicator on the PRT platform.
Do you want to see only the last value of the whole ones through data history? (in this last case, the appropriate solution is the one given by Vonasi = use Donchian channel).
i tried Donchian Channel indicator and this is not what i was thinking of. I just basically want a horizontal trend line showing the price for 10 day low and high