Unfortunately though your question is too vague for me to respond to in detail.
In general, I'd say that selling software for any platform is much harder than writing the software. I recommend finding customers before coding.
Second, I'd recommend being laser focused. Decide what the program will do. Stick to that. Don't get trapped in the "if it just did x I would buy it" messaging.
Too often I see programs that are difficult to explain, and have weird interfaces because the developer didn't say no to himself as feature creep happened.
okay, if you were me, how would you have refined the question? interested to know:)
Are you asking "before" you've written something, or "after"? Are you looking for a market to explore, or a market for something you have?
Is the market broad-based, or narrow?
Is it expensive (say > $1000) or cheap? (say < $50). Are you looking for a subscription or an out-right sale?
Are the competitors in your market? Is this a new market? Are you "cutting edge" (think crypto, ai etc) or boring (think accounting etc)?
Is it data for one person, or shared by multiple people, or a business?
Soooo many questions....