Polls and surveys are great ways to integrate low-stakes engagement or gather quick feedback on how students are doing. Some common reasons and ideas for including polls and surveys in your classes include (but are not limited to):
needs assessment to better understand your students, their backgrounds, their interests, and their motivations and to enable them to provide input on the topics and activities in the course
using a poll before a lesson to spark students’ curiosity
following up a lesson to have students actively reflect on what they've learned before moving on
gauging students' readiness, feelings, motivation, etc.
gathering feedback from students on your content, your activities, or your teaching style