Edit Text in a PDF on an iPhone

I have just spent an hour with technical support web chat trying to get an answer to my question but they refused to help, instead directing me to this help forum, I logged a question on a similar page but then the question was rejected, so I am starting again. I really hope that someone can answer my question because I am all out of ideas where to go from here.

Adobe made a big song and dance when I was purchasing the product that i could edit PDFs on my mobile device. Excited with the flexibility this offered, I immediately signed up and paid for my subscription. I then went to my mobile device to edit a PDF and was disappointed as there was no edit option? I signed out, signed back in, rebooted my device. Watched tutorials but nope. Still no wiser.

See screen shot, there is no edit mode on my iPhone?

Please advise what the problem is - thanks.