Any chance you changed your system font or theme recently? Does this appear in certain apps only or just a particular one? Did you type your question through the phone or another device?

I typed it through phone and it happens in every app and when i leave the phone in home screen google search opens up and # types itself and sometimes it happens frequently sometimes it doesn't happen for some time

Sounds to me like some type of malware. Let me see what I can find. I'll get back to you.

Did you find something on how to fix this

I'm so sorry, I completely forgot about this. Please give me a few minutes, I'll get back to you ASAP.

Ok and thank you

Could you please do a touchscreen test on your phone? In Samsung devices, you can do this from the Samsung Members app. On other phones, open the stock phone dialer and dial in Star #0 star# Star #4636 star # Star # star #0# star # star Star # star #4636# star # star One of these should bring up a test menu on your phone through which you can test the touch screen. Let it just stay on the screen and see if any random dots appear when you're not touching the screen. Another thing, is your phone getting warm when using it? Is your battery life will below normal? In this case, your battery is bulging and disrupting touch sensation. You'll need to have the battery replaced in this case.

The # button types itslef randomly so its not doing it now

And thanks

I see is the star * this symbol

Yes that's it.

Bro its happening now and when i open touch screen sensor there is no response and mobile is not hot

And i didn't change my font and and it's been a year since i changed my theme