mbunband

If you're using a computer with a keyboard, look for the "Print Scrn" Button which should be located above the number and F keys if you're utilizing a standard keyboard. Once you have done that, open up paint and just click the Paste option and it should transfer over. You can also Paste on to Microsoft Word as well and adjust the image square to the size of your liking so the messages are still readable. From there Save As whatever file type you'd like and print. 
 
Also, if you utilize a Facebook Messenger App, you can open the app and screenshot as you would with your telegram or WhatsApp.
 
Hope this helps.

I was thinking the same thing. Uploading a picture would have been handy.

Hello,
I just recently completed my case at the NVC so I am pretty familiar with what needs to be sent from my experience and understanding. NVC will typically just need last 3 years of Tax Return Transcripts which can be obtained via the site that was given by steve770. You can also create an account on the IRS site and obtain your Tax Transcripts digitally if you are pressed for time. If you intend on sending Federal Tax Returns, then you will need W2s from those years to be sent in with them as well.
As for exact documents, you or petitioner will need to follow the "Welcome Letter" which you should have received via email. That letter has a checklist that you need to follow and send in each document pertaining to your case. For example, Cover Letter, I-864, Tax transcripts, marriage certificates, etc. My package was almost identical to that which you send to USCIS but varies slightly with the financial supporting documents. I followed that checklist for the AOS and they did't request any further for the IV as it is pretty much corresponds with each other.
As the beneficiary, you do not need to sign any documents. Your spouse will need to provide a signature for the I-864 for the AOS Package. I am the petitioner for my wife and did everything on my own without requiring any of her signatures. If you have any questions, please feel free to ask and I can help out as much as possible.