Weed killer

If you wish to eradicate all plants in the area, then you would choose a non-selective product that contains glyphosate. Below is a website with more information about these types of products.
https://www.canr.msu.edu/news/understanding_roundup_products

Apply the product per the instructions on the container and then wait a few weeks to see if a second application is needed. We do not recommend that you put down a plastic covering since that doesn't allow moisture to drain into the soil. Rather, a good layer of mulch (3 - 4 inches in the first application) will suppress new weeds , provide protection for plant roots and conserve water. Keep the mulch a couple of inches away from the plant base to prevent insect activity and leaching of nitrogen from the plant. Below is a good article about the types of mulches which can improve your soil and control weeds. https://www.canr.msu.edu/resources/smart_gardeners_improve_their_soil_and_weed_control_with_organic_mulch

Hope that helps.