Please go to your Form Settings >> BuddyPress Settings. And make sure you display the form as Tab or Sub Tab
1. Set it as Tab: You can find it on the tab of your Profile Page
2. Set it as Sub Tab: You can find it on the Post Tab of your Profile Page. You also can edit a post by click edit button on each post list
3. By using Shortcode : You can copy the short code on the form settings and put it on any page you want.
If you use short code and put it on a Public page, you can set the Anonymous user. That's mean, user can submit post without login
