I have a question in which I want to request feedback about my software. Am I allowed to ask this type of question here or it will be considered off-topic here?
This would be off topic, and may well be flagged as spam.
If you have a specific question about the design of a particular feature in your software then you could ask a question about that.
If you have a specific question about one aspect of the User Experience your software delivers then you could try asking on our sister site on User Experience.
Asking for generic feedback is considered both "too broad" and "primarily opinion-based", making it not suitable for Stack Exchange.
However, if you have specific questions about your architecture, design, use of data structures or algorithms, testing, or any of the other topics that are allowed, you can ask those, but you need to be specific about a problem and not soliciting general feedback.
If you need assistance with reviewing working code, check out Code Review. For specific usability questions, check out User Experience. If you're having problems with implementation or tools, check out Stack Overflow.
So long as the issue is about design and not actual code, and it's presented as a solution with cons, you may ask the question "How could I correct this design to resolve issue(s) X, Y, Z?".
These questions can be on the fence but structured properly we've had some high quality questions of the nature in the past. Have a look at these as similar but well-asked design questions:
How to refactor to cleaner version of maintaing states of the widget
Recommened design pattern to handle multiple compression algorithms for a class hierarchy
OOP Design - Possible wrong approach makes it impossible to implement it in code
Notice these all had to narrow their design questions down to a given issue (whether perceived or real doesn't matter) and asked how to make their design solve for that.
So you can get feedback on your designs for sure, you just have to structure your question correctly to give people a problem constraint which they are to change your design to solve.