Do you have an id on you?

[Tdol]

That's a pragmatic approach I could go with. I have lived in countries where I had to carry identity cards and ones without.

 

[Rover_KE]

I am extremely sorry for this but I am confused between "id" and "ID".

To bring the thread back on topic, acronyms and initialisms are almost always capitalised to prevent misunderstandings like this and to make them stand out in the surrounding text.

Thus, we don't write 'Holden McGroyne struggled with aids for years' or 'Throughout her teaching career, Dot Matrix was an active nut member'.

However, there are exceptions, such as 'nimby', 'radar', 'mph' and I've recently been seeing 'Fifa' and 'Uefa' in football reports, but when in doubt, capitalise.

 

[Tdol]

And avoid lower case when it could be confused with a word, which is the case with ID/id.

 

[tufguy]

See above.

Think of "ID" as an abbreviation for identification document. In Freudian psychology, the id is one of three key components of a person's personality.

Okay, got it now. Thank you.