How do I add a signature?

[DMW5150]

I have already been to "composing and  sending". I have app set to rich text. There are two checkable boxes, but both are already checked and whited out so that I am unable to click on them.

[StR]

There are two checkable boxes, but both are already checked and whited out so that I am unable to click on them.

This description is not quite clear.
Could you, please, post a screenshot?

[mikeone]

I have already been to "composing and  sending". I have app set to rich text. There are two checkable boxes, but both are already checked and whited out so that I am unable to click on them.

To define a signature go to the Account-specific settings:
-> long press on account name -> Options and folders -> Composing and sending -> tap on 'Signature' -> enter your signature text (to add images and/or hyperlinks: tap on the bar "Switch to rich text")

-> see screenshots for details