I have just written a short description (a few paragraphs) for a small software project. Not being a native English speaker, I'm looking for a few people to proofread it, correct mistakes and improve style.
Is it OK to ask on this website?
It all depends on how you ask the question. It would be considered a critique question, which is on-topic, and must conform to our guidelines. The most important guideline is that you must be asking a specific question about your paragraphs, not just "Please improve my description." So while our excellent community is likely to improve grammar as well as style, we most of all need to know the question you are asking when you come to use for a critique. Examples might be:
The more we know about your goals for the description the better a critique we can provide.
And please, whatever you do, give it a title other than please critique this or something similar. Make your title descriptive of the question.