Qualtrics
Qualtrics is used to create questionnaires and surveys. It is the most full features and "high powered" of all the survey options. See the ITMS pages for more information.
For most applications, MS Forms will likely suffice. It is part of the Office 365 suite that all faculty members have access to. MS Forms permits either anonymous or authenticated responses.
If you wish to survey students in your class, the survey feature in LEARN can often suffice. On identified disadvantage to LEARN surveys is that you cannot do "branching" where subsequent questions depend on previous responses.