I have installed the awesome OpenTTD on my android device. Unfortunately, when I tried to join multiplayer it appeared that I wouldn't be able to click the button to start a new company. The window doesn't fit on the screen.
The Android version of the game has the Big GUI NewGRF loaded by default. This enables the game to be actually playable on tiny phone screens by doubling the size of most UI elements, but in your case it appears to have made things too big.
Simply disable the NewGRF mod from the NewGRF menu to shrink the buttons back to their original size, but do note that the game would be rather unplayable with a screen that small and the Big GUI mode disabled.