Need to correct sentences or articles

Hello , I’m a new member. And, I’m not strong. I can’t express well. I watched the video which was made for new comers. It teaches me how to use this website. Now, I have questions. If I need to write somethings. Is there anyone can help me to correct it? How to use the part of this website?

You can send your phrases using the opportunity ‘Writings’.
But you need to buy some points for it before.

OK, thank you for your help.