Sending attachments to non-Apple people-- the green ones-- can fail with an "Attachment is Too Long" error. Here's how you fix that.
How to Fix iMessage “Waiting for Activation” on iPhone
Is iMessage on iPhone stuck, "Waiting for activation"? Apple's suggestions don't always work. Here's how to activate iMessage the right way.
How to forward (or delete) part of a text message conversation on an iPhone or iPad
Delete or forward part of text message conversations on your iPhone, maybe NSFW photos. You can delete an entire conversation; this is better.
How to sync text messages between your iPhone and your Mac
You want your iPhone's text messages to sync with your Mac and iPad-- all messages, green and blue both. Here's how you set it up.