What is the name of this herb plant?
No guarantee that my answer is the right one but my educated guess that your plant is a species of Acalypha. There are a number of species in this genus and I'm sorry I can't narrow it down further.

The shape of the leaves, the little 'pig-tail' shaped seed (or unopened flower) spike seen in the upper left corner of the first photo, the tinge of pink on some leaves and veins and even the twist or curl on the uppermost group of leaves leads me to think that.

I'm including some photos showing these points. Whether it's a plant in this genus is for you to decide. It would be helpful to know the size of the entire plant and he range of size in the leaves.

Acalypha wilkesiana



Another Acalypha wilkesiana with this one showing the 'pig-tail' flower spikes better.



The flower spikes are very evident in this Acalypha bamentacea here.



The twists and curls can be seen in this cultivar of Acalypha wilkesiana.


Source courtesy of Dave's Garden