You can post screenshots a number of ways.
1. Selecting the "Photos" option
2. Selecting "choose files"
3. Pasting directly into the body of your message
@Jay , I don't think those options are available when accessing the community from the iPhone.
Yeah, that's it. I wish the mobile site provided options, and maybe it will in the future. Do you have any access to a laptop or computer? Alternatively, the mods here may provide an email address where you can send screenshots, which you can take from your iPhone. (Not sure if there is such an email address, though).
Also, when you are able to post the screenshots, I recommend avoiding any screenshots that may contain personal information such as your address, phone number, or account number.