Auto select drop down if another cell contains certain words

I am trying to categorize expenses from a credit card statement. Currently, to do this I am manually choosing the category or "code" in column H for every expense. We have to do this for every charge and most of our vendors are always categorized to the same category. For example if "SPEEDWAY" is in the Description (Column D) then it should always be categorized as the code "Auto & Truck" in the dropdown list in Column H.

Likewise, if the description contains "RINGCENTRAL" then the code is always telephone.

How can we auto populate the correct category in the dropdown in column H if column D contains certain words?

If the vendor is not recognized then I would like to manually select the category or "Code" from the drop down.

Thanks in advance for any help!!