Hi Billy and welcome to JustAnswer,Thank you for the question and your patience. Should you still need assistance for information purposes only...Initially, bear with us; re-confirm and post back with the complete model number of the "...LG phone..."
Still, but depending on the phone model, features and operating system, there are utilities that can "tap" the system of the phone and view/save in a computer:
The LG LGMS395 is a smartphone with Android 4.4 KitKat and can use text / SMS Messaging Communication; i.e. send SMS & MMS text messages from a PC, Mac, or Tablet. Please click HERE.
I need to print out a txt conversation that is in my phone
If you would click on the above linked HERE, then it would open to a page with instructions on how to install the "PC, Mac, or Tablet SMS Messaging Communication".
Once installed, then it would open a page in a browser and the text messages in the phone would be shown likewise in the computer. Thereafter, the text messages can be copied and/or a screenshot of the computer screen showing the displayed messages may be made.
Please see the screenshot of a smartphone text messages as shown in a computer screen HERE.
The above would be the easiest and simplest to implement.