Screenshot help, could it be fake?

My dad and my stepmum rented their house out and they evicted their tenants and now on of the tenants has sent me messages saying that my stepmum has said nasty things, really disgusting things about me, my son and my unborn baby. She sent me a screenshot that apparently my stepmum had wrote to her and it does have my stepmums number but I want to know if screenshots can be tampered with? I'm not sure what the phone is, I'm assuming it's an iPhone but as I said I don't know. If anyone knows if you can fake them or knows how to do it please let me know because it's very important.

It's easy to fake anything on a computer or a phone, no special skills needed.
Think about this:
Of course they have contact details, they were tenants.
Why do they have your details?
Why involve you at all? Were you close friends with them? If not then why tell you at all?
Why would your step mum send these things to them?
Why were they evicted? You have to have cause to get an eviction, damage, non payment etc.
Sounds like a vindictive person trying to stir things.
Show your step mum the messages, her reaction will tell you a lot, don't accuse her, just let her see what they are saying, you may be able to sue them for libel and hurt.

I just want to add that there are entire internet sites dedicated to allow people to create fake iPhone conversations.

You type in what each person says, and it generates an image that looks exactly like a real screenshot.

What springs to to my mind is why are you considering this at all? She got evicted, she will be bitter
anything on a screen can be printed and altered. I think one of the words in your question
is your answer. STEP MUM

I just want to add that there are entire internet sites dedicated to allow people to create fake iPhone conversations.
You type in what each person says, and it generates an image that looks exactly like a real screenshot.