You must sign a [Contribution License Agreement (CLA)](https://cla.opensource.microsoft.com/) before your PR will be merged. This a one-time requirement for Microsoft projects on GitHub. You can read more about [Contribution License Agreements](https://en.wikipedia.org/wiki/Contributor_License_Agreement) on Wikipedia. However, you don't have to do this up-front; you can simply clone, fork, and submit your pull-request as usual. When your pull-request is created, it is classified by a CLA bot. If the change is trivial (i.e. you just fixed a typo) then the PR is labeled with `cla-not-required`. Otherwise, it's classified as `cla-required`. In that case, the system will also tell you how you can sign the CLA. Once you have signed a CLA, the current and all future pull-requests will be labeled as `cla-signed`. Signing the CLA might sound scary but it's actually very simple and can be done in less than a minute.