Snapchat is one of the most used social media applications all around the world and their Android app has a beta program available. First, you can check out our guide, which explains deeply How to become a Snapchat beta tester on Android.
To start with, there is a feature in Snapchat beta called 'Shake To Report'and it is made to report bugs/issues. It is enabled by default and you can shake your device when you are in the app to report an issue. You will be greeted with a pop-up menu, which has three options. The first one is 'Report a Problem' and this is what you need. The other two are 'Suggest Improvement' and 'Turn Off'.
Other than that, you should include a detailed explanation of what happened and the steps to reproduce it. The more information, the better! Also, the Snapchat app sends a screenshot with the report, so if there is a UI issue, then you are covered.
As you can see, this is not that complicated of a process, but it is very helpful to report problems if you want them to get sorted out.