Have you really wanted a feature in Premiere? There is a method to request that for future versions, or updates.
Have you discovered a real Bug in Premiere, and need to report that to Adobe? The same place will be used for this.
Go to the Feature Request/Bug Report page.
Now, my first advice is to check that your desired "feature" does not exist, but you have just not found it. Posting it to the forum will likely get you direction on how to do what you want, or where to look for it.
If you've found what you think is a Bug in the software, I'd also post about it here, as it might not be a Bug (they do exist, but are way, way down the list of causes for hangs, crashes, poor behavior, etc.), and others can then confirm if it IS a Bug.
In your initial posts to the forum, please provide all details, on what you want to do, or on what is happening, with which Assets/Project, and on what equipment. Please see this ARTICLE for tips.
Now, let's say that you have a good feature request, or have found a Bug. When you contact Adobe, be sure to list the same info that you posted to the forum. They will need to have that, to evaluate your feature request, and definitely need it to go to the lab, to replicate your issues, and begin fixing the Bug. Without that info, they stand little chance in the lab.
Adobe takes both the feature requests and the Bug reports seriously. Now, there could be reasons that you do not see your feature appear in the next update, or upgrade. It could be that you are the only one asking for such, and/or the coding for that is too expensive, or might break something else. It could also be easy to add, but Adobe was too far along the development cycle to get it in the next version.
With the Bug reports, after Adobe does replicate the issue, some of the same considerations might come into play. It could be that coding will take a long time, or might also break something else. These fixes must be extensively tested, and on a lot of different equipment. Also, remember that many Adobe programs are X-platform, so a Bug fix for Windows, might cause real issues on a Mac. All of this takes time and effort.
Just some things to think about,