What is the name of this plant with small leaves? Is it bad for my palm? Should I keep it or remove it? Or can I replant it into another pot?
I don't recognise it currently, but if there's any chance it's something you might want to keep, extract it carefully now, keeping the roots as intact as possible without damaging the roots of the palm, and pot it up separately. All the time its growing there, its stealing a tiny amount of nutrients and water from the palm, but worse, the roots are getting larger and intertwining with the palm roots - if its something you want, you won't be able to extract it successfully later, and if its something you don't want, it'll be difficult to get all the roots out so it doesn't grow again.
The likelihood is, it's something you don't want, but either way, it needs to come out of that pot now.