To create a post using a custom or an avatar-themed visual, you can use built-in social media tools or design platforms to layer your text and graphics. Facebook Avatar Post

Since 1500x896 is a specific landscape resolution (common for some blog headers or desktop wallpapers), you can use design tools to "put together" a professional post:

Pick a pose or background that fits your 1500x896 theme. You can also edit your avatar's appearance if needed.

and tap "What's on your mind?" to start a new post.

Type your message over the avatar graphic and tap Post . Designing a Custom Post (1500x896)