Thanks for your question.

From the two pictures you sent us, this seems to be a Spurge plant. I cannot with great confidence identify the precise species. It is an annual plant meaning that if you do nothing, it will die at the end of the 2024 season. It will soon produce large numbers of seeds that will germinate in spring 2025. For that reason, you should apply a broad leaf herbicide NOW before it blooms and goes to seed. If you fail to do this, this plant will be visiting you again in 2025. See:

https://ipm.ucanr.edu/PMG/PESTNOTES/pn7445.html?src=302-www&fr=4674

Good luck. Please don’t tarry in dealing with this. Thanks for consulting us.