I have fat fingers hence this makes typing on the Iphone which has a small screen difficult , I always mistyped
Are there any ways to overcome this problem ???
Practice makes perfect, but the real differentiator between people that struggle to learn to type on glass and those that become proficient is the mindset when you learn.
I would encourage anyone struggling with this to give themselves a huge window to learn. Play around with the keyboard for 5 minutes, don't worry about your fingers covering the letters.
Also, when playing - see if you can place your finger in the empty zone between three characters (two on one row and the key below the gap). Plop your finger down but don't lift it. Then pivot it gently, rolling on the fleshy part of your finger and see how the contact area changes as you rotate your finger. You can drop your finger where you think the letter is and then adjust before lifting.
After playing a bit, you will quickly get better as long as you don't get too frustrated with yourself. Just as learning to ride a bicycle can be hard initially, this too is a fine motor skill you need to practice.
I've never met anyone that couldn't learn to type due to physical limitations - the only people who don't seem to pick up this skill have barriers in their brains where they are too impatient, too busy, too frustrated or just don't care to learn a new skill. There's nothing wrong with any of that, but if you give yourself a few days to adjust I think you just may start to like the keyboard or at least reach a level of peace and possibly comfort with how the touch detection works.
I recommend turning the phone into landscape mode whenever possible (sideways orientation). This allows the keyboard to become significantly larger with each key being larger and having more space in between it and the next one.
There are some apps that are portrait only; they prevent you from using the landscape keyboard. However, many, probably the majority of, apps allow landscape mode. Basically all of the text-entry apps do allow landscape mode such as Messages, Email, Notes, Evernote, and the like.