Wide-legged standing forward bend
The name of the pose pictured is prasārita-pāda-uttānāsana
Prasārita = spread or apart pāda = legs or feet uttāna = upward extension; "ut" indicates intensity āsana - posture
It has certain characteristics worth mentioning. In particular, it is a standing pose where the feet are wide apart, the legs are stretched, the torso is completely bent forward with the head resting lightly on the ground and the hands also resting lightly on the ground. One can place the hands and arms in different positions, such as depicted in the photo.
The idea is to maintain as straight a back as possible with ones weight on the feet and the legs properly stretched.
There is a natural tendency for the back to round in forward bends, but with this pose an effort may need to be made to flatten the back.
The pose is riskier if the feet are too far apart. One way to check that you have not stretched out too far is to see whether you can step your feet back together in one easy controlled movement. While moving into and out of this pose using the heel-toe heel-toe method can be used, it risks you going to far. I would suggest stepping out and back as safer and more instructive.
The pose is also riskier if the back is rounded and the head is on the floor in front of the body. It is also risky if there has been too little or no suitable preparation. If the pose is not agreeable to the body and the breath, then it is a risky pose. Come out of it slowly and carefully if you have misjudged your fitness and capacity for this āsana.
Often we forget that the journey is as instructive and enjoyable as the destination. If this pose is an appropriate one for you but you can't yet reach the final form comfortably and steadily, then be content to use an intermediate stage. Also, work with and enjoy preparatory āsana-s like pārśva-uttānāsana [flanked forward bend], ardha-uttānāsana [half forward bend] and utthita-trikoṇāsana [triangle pose] first. These should be mastered before trying to master prasārita-pāda-uttānāsana.
A mistake people can make is attempting an āsana without properly considering its consequences to the body, breath and mind. So, please do not undervalue or ignore the role appropriate pratikriyāsana(-s) [counter pose(s)] play in a well-rounded practice.
Generally, we don't want to be lying down and relaxing straight after practising prasārita-pāda-uttānāsana.
Counter poses, like preparatory ones, should be considered with respect to the fitness, capacity and intentions of the individual concerned. For some utkaṭāsana (squat) done in a relaxed way may be the way to go after the pose being discussed here. In addition or instead, one might practise ūrdhva-prasṛta-pādāsana, dvipāda-pīṭham and or apānāsana.
You may know the poses I have named by other names. I'm quite happy for you to call them whatever you like 😃. Also, there is a lot more to prasārita-pāda-uttānāsana than sketched out here.
If you want to know more - for instance, how the breath can support the āsana, what variations and modifications could be applied, when and why, what the contra indications might be, and what bhāvana-s will help - then ask your teacher if she or he would be willing to explore it with you.