A beta feedback survey asks early users what to fix before a feature launches to everyone. This template keeps it to four questions and a little over a minute: an overall score, two open questions on what worked and what didn't, and how likely testers are to keep using the feature once it ships.
It is written for an email to your list of testers about a week after they get access, and for a link you share in the beta's own channel, such as a community thread or the welcome document. In your web app, the same survey can open as a popup for the users in the beta.
Every written answer is read as it arrives and filed under a category such as ease of use, speed and reliability or features and gaps, with a type, so bugs and ideas arrive sorted. Results shows the average score, the share of testers likely to keep using the feature, and the themes in what they wrote.