This is a very simple thing that should work immediate if all your setup is correct. Mainly utf-8 for English in installed_languages.inc and the default font dejavu  mentioned in class.pdf.inc and that the font files are in /reporting/fonts. Thats all. Unless you have /reporting directory somewhere in /company/x that is overriding your changes. So please review your installation.

You need to change the English encoding to utf-8

C    English    utf-8    No    Unknown    None           

I have changed the English encoding to utf-8, But even then, writing a note in Urdu when English is the default makes that Urdu question mark in the PDF.

You need to change the English encoding to utf-8

How can I change it?  Please guide me on this.

Can you list here the contents of your /lang/installed_languages.inc

Also make sure that

                    default :          $fontname = "dejavu";         break;

is specified as the default font around line 162.

My list here the contents of my /lang/installed_languages.inc

<?php

/* How to make new entries here for non-packaged languages:

-- 'code' should match the name of the directory for the language under \lang
.-- 'name' is the name that will be displayed in the language selection list (in Users and Display Setup)
-- 'rtl' only needs to be set for right-to-left languages like Arabic and Hebrew
-- 'encoding' used in translation file
-- 'version' always set to '' for manually installed languages.
-- 'path' installation path related to FA root (e.g. 'lang/en_US').
*/

$installed_languages = array (
  0 =>
  array (
    'code' => 'C',
    'name' => 'English',
    'encoding' => 'iso-8859-1',
  ),
  1 =>
  array (
    'name' => 'Arabic',
    'package' => 'ar_EG',
    'code' => 'ar_EG',
    'encoding' => 'utf-8',
    'version' => '2.4.1-3',
    'path' => 'lang/ar_EG',
    'rtl' => true,
  ),
  2 =>
  array (
    'name' => 'Urdu',
    'package' => 'ur_PK',
    'code' => 'ur_PK',
    'encoding' => 'utf-8',
    'version' => '2.4.1-3',
    'path' => 'lang/ur_PK',
    'rtl' => true,
  ),
);

$dflt_lang = 'C';

Also make sure that

                    default :          $fontname = "dejavu";         break;

is specified as the default font around line 162.

Make sure that the language encoding is utf-8 then go:
https://frontaccounting.com/wbt/pages/download/downloads-for-release-2.3fonts.php
Download and install dejavu font as described in the instructions.

Also on the same page take a look at the Font Utility Package if you want to use your own fonts.

Doing it this way has not solved my problem۔

Also on the same page take a look at the Font Utility Package if you want to use your own fonts.

.repclass tbody tr td a {
    font-size: 12px;
}

Note:- .repclass a {... should work, but not tested

That will do only the Reports For Class: list, to change the report classes: list read the following:-

How do you see what css affects what element on a page?
Either press the F12 key OR right-click on page element and select 'Inspect'(Chrome) or 'Inspect Element'(Firefox) You should now see a panel showing html and another panel showing the relevant css.

Have a play

Tips -
You can change what you want and instantly see the results(They are not saved, to cancel changes just press page refresh), then make the changes in the css file.
In Firefox only (sadly not chrome) if you right-click over an html element(in html panel) select 'Copy' then 'CSS Path'; paste that into a text editor and you will see the complete css path, shorten as necessary, then use.

Google 'how to use browser developer tools' for more info

I guess you are right with the browser font -/+..but we really need to fix the starting font size.. Its minute with English and with Arabic its minuscule. I looked into the default.css and could not decipher where this font size is defined. I meant when one chooses Reports and Analysis (../reporting/reports_main.php?Class=6)

Thanks..

I am getting there. One last thing .. Where can I change the font size of the Reports and Analysis screens?

Appreciate your help.