T-Mobile doesn't save copies of texts. Once they're delivered, they're done.
This would be like asking if T-Mobile had copies of phone conversations.
The only thing you can get is a record that a number texted you, or you texted a number. You can get these from your bills for the past 12 months. If you need further back, T-Mobile can get them for you, but there will be a fee. You can contact Customer Care for that.
For the future, if you need printouts of texts, I recommend utilizing a backup application for your texts and printing them from that. There's several backup apps out there, depending on your device. Try out a few to see which one(s) give you the features you need.
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