As a perennial weed, it will require either digging out, repeated cutting-down, or treatment with a systemic herbicide (glyphosate being a typical ingredient). If cut down to avoid herbicide use, remove all above-ground growth promptly every time it reappears, as this will help to speed-up the depletion of root energy stores. Every time a plant is forced to replace growth, it's using-up stored energy from the roots, so by depleting it through forcing continual regrowth, eventually the plant will starve and cease returning. You'll need to be vigilant for regrowth since the longer it can photosynthesize, the more that will prolong it's ability to keep coming back, since it can send carbohydrates down into the roots again to "recharge" them.

How long that approach will take to finally kill the weed is hard to predict. The plant pictured doesn't look very mature or large, so it might only be a few weeks as opposed to at least one growing season. If you do opt to use herbicide, you can spot-treat its foliage carefully so spray does not drift onto any nearby desirable plants, as glyphosate and other chemicals do not discriminate and could damage other plants that receive enough spray drift. It might take a week or more for the treated weeds to succumb, since the chemical needs time to move from leaves into roots and then cause them to die off.

Miri