Hello shahin_touhid,

For doing Zoom in that is for making text bigger in size simply press and hold 'CTRL' + '+'. That is press and hold CTRL key and then press + sign key to zoom in text according to your need.

For Zoom out that is to make text size smaller Press and hold CTRL Key and then press - sign key. That is 'CTRL' + '-'.

You can also do the same using View menu from toolbar.

Simply press CTRL+0 for normal view.

Please reply back if you find this helpful.

Thank you..

Hi!

Just want to make sure which OS you are referring to for this. Firefox OS or Windows 7/ Mac?