How to print text messages from an iPhone for court

The free ways, and what each one misses

Screenshots: free and quick for a few messages. Times show only as an occasional header, the other person appears by contact name, and long threads become dozens of images that are hard to keep in order.
Swipe left in the conversation before each screenshot: the iPhone then shows the time next to every message, but still not the date on each one or the phone number.
Print from Messages on a Mac: if your iPhone syncs to the Mac with Messages in iCloud, open the conversation, scroll up until everything you need has loaded, then choose File, Print. The printout follows what is on screen. See exporting iMessages to PDF on a Mac.
Copy and paste into an email or document: the text comes across, but the times and senders usually do not.

What a printout for court usually needs

Requirements differ by court and by case, but lawyers tend to ask the same things. Our page on what lawyers ask for goes through them in more detail.

The date and time of every message, and the time zone.
Who sent each message, with the phone number or email address, not only a contact name.
The whole conversation, or every message in a stated date range, with nothing skipped.
Photos and other attachments, either in place or listed so they can be matched up.
Page numbers, and Bates numbers if the case uses them.
A note on how and when the printout was made.

Step by step with TextExhibit

On your Mac, open TextExhibit and choose where the messages are: the Messages app on the Mac, the iPhone over a cable, or a backup already on the Mac.
Find the conversation by name, number or a word in it, and pick a date range if you only need part of it.
Check the preview page by page. Add a case name, an exhibit label or Bates numbers if you were asked for them.
Export. You get one PDF, the original attachments and a hash list in one folder. Print the PDF, or send it as it is.

What to keep in mind

This is general information, not legal advice. Whether the court accepts the printout is up to the court and the rules where you are.
An export shows what is on the phone or in the backup. Messages deleted before the backup was made are usually not there.
Someone with knowledge of the messages may still need to confirm in court who sent them. See how to show texts are real.

Questions

Can I print text messages straight from my iPhone?

Not as a conversation. The Messages app has no print option for a thread. You can print screenshots from the Photos app with AirPrint, one image per page.

Do I have to print the whole conversation?

Often the other side or the court wants enough context to see that nothing was left out, so lawyers usually prefer the full thread or a full date range rather than hand-picked messages. Ask your lawyer.

Should the printout be in color?

A black and white printout of an export is readable, because it does not rely on blue and green bubbles to show who said what. Bring a color copy too if the photos matter.

How long does it take with TextExhibit?

Reading a conversation and making the PDF takes minutes. Making a fresh backup of a full iPhone over a cable can take longer, depending on how much is on the phone.