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Populate the user message parameter with content a user manually entered earlier in your app's flow.
Your app’s composer can include a call-to-action that disappears when people start to write a post. For example, Facebook's composer uses grey scale text to ask “What's on your mind?” that disappears when people start to write.
Pre-fill the user message parameter with any content the user didn't enter themselves, even if they can edit or delete that content before sharing. This applies to posts, comments, photo captions, and photo album captions.
Add your own content to that which the user manually entered. This includes hashtags, hyperlinks or URLs.
Prompt users to click or tap a button to auto-populate the user message parameter. Your app can suggest content, but the person using your app should choose to manually copy and paste or type that content themselves.
Pre-fill using the iOS share sheet. For apps pre-filling using the iOS share sheet we recommend that you either remove all instances of pre-fill from your app and submit an update to Apple's App Store or use
Facebook's share dialogfor a more seamless experience.
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