Upper case

[silvergold]

Is it permissable to write a formal letter all through with upper case alphabets?

[5jj]

There's no law against it, but it would seem very strange. It would not give a good impression.

ps. welcome to the forum, silvergold.

[Rover_KE]

Writing entirely in upper case letters is considered to be SHOUTING, silvergold, and therefore rather rude in any kind of communication.

A legitimate use of capitalisation is following your signature — like this:

Yours faithfully,

[illegible signature]

PHIL MACAVITY (MR)

Rover

[emsr2d2]

Is it permissable to write a formal letter all through with upper case alphabets entirely in upper case/entirely in capitals/entirely in capital letters?

Online, writing everything in capitals is certainly the equivalent of shouting. If you are going to write the letter by hand, it really depends on your handwriting. I have a friend who writes entirely in capital letters but his writing is very neat and quite stylised, so you almost don't notice the capital letters. However, as a general rule, regardless of whether you are writing by hand or on a computer, use the standard rules of upper and lower case lettering.