How to increase font size for Urdu Language

Well, to answer my own question: the problem was that my GPU was overheating.

I forgot to mention that this specific machine is a hackintosh. I don't know if such thing can happen to a real Mac, but anyway: here where I live it's pretty hot and dry, so there's a lot of dust accumulation inside and around my computer. The GPU cooler stopped because of this (last time I cleaned it was back in March), so I just opened up the computer case, cleaned it and now everything seems to be back to normal.

There are several ways to do that.

The easiest way would be to install a Plugin which formats outgoing E-Mail and give you the option to change specific characteristics to you liking (Font, Size etc.). For that you should look into the following Plugins:

1. MessageFont

   "WYSIWYG for your outgoing emails If Outlook for Mac, Thunderbird and other email apps can set the default composition font1, why can’t Apple Mail? With MessageFont, you can! MessageFont lets you set Apple Mail’s default composition font for new rich text outgoing messages. [...]"

2. Universal Mailer

   "Universal Mailer is a Mail.app plugin that solves some issues when sending emails. It removes ATT00001.htm files, it correctly formats messages with attachments and inline images and offers an option to set the default font for outgoing messages. [...]"

Another way would be to change the default Font Size via the Terminal, f.e. in 24, open up the Terminal and type in:

defaults write com.apple.mail MinimumHTMLFontSize 24

That will change the Font to 24pt, but that includes the Page you want to forward from Safari if you choose 'Webpage'. If you just forward the Link everything should be fine.