What Should You Capture: Facebook
If someone "liked", "reacted" or interacted in any way with something you posted, you can often click on the content to see a list of people who interacted and responded. You can screenshot this to show the interaction. If there is an order of protection in place, even a "Like" on a Facebook post could be considered a violation of the order.
To connect posts or comments with a specific person, you will need the profile information of whoever posted the message or the comment. Click on the person’s name to be taken to their profile page, which should include name, profile picture, and other public information. Even if the other person has made their account private, Facebook will always make publicly available the name, username and user ID, profile picture, cover photo, gender, and networks. Copy the URL of their profile page to get the unique identifier that will be needed to identify the person.
has a Download Your Information Tool
that will let you download everything connected to your Facebook profile, including posts both you and others have made on your timeline, comments, likes and other interactions. This can also be used to document posts and preserve evidence of abuse, as long as you start the download before the person deletes the activity. This can be helpful back-up to any screenshots you are saving of Facebook activity.