Look at any official letter. Your name is in capitals. JOHN ADAM SMITH. This is not a typographical accident. In legal drafting traditions inherited from admiralty and commercial law, all-capitals signals a corporate or fictional entity, distinct from the natural person whose name is normally written in mixed case.
The argument runs that JOHN ADAM SMITH and John Adam Smith are, on the page, two different parties. The capitalised version is the legal person, the trust, the corporate fiction. The mixed-case version is the living being.
UK courts do not recognise this distinction in practice. They will treat both spellings as the same party. But the convention is real, and noticing it is part of waking up to how the paper world is built.
In your own correspondence, use mixed case for your own signature and reserve capitals for the entity you are addressing. Sign John Adam Smith, not JOHN ADAM SMITH. Small thing, but consistent.
Reality sidebar
Refusing to answer a summons because the name is in capitals will not work. Courts have ruled on this many times. Note the convention. Use it in your own drafting. Do not stake a defence on it.
What to do with the convention in your own correspondence
The one practical use of the capitals convention is in your own letters and signatures. When you write to an authority, address the legal person in the form they use: capitals, full date of birth, reference number. When you sign, sign as a living man or woman: lowercase autograph, "by [your name], a living man" or similar, and where helpful add "all rights reserved" beneath. This is not a magic ritual that defeats the matter. It is a small, consistent reminder, in your own paperwork, that you can tell the two apart even if the court cannot. Done quietly, every letter, it is part of the disciplined posture the rest of the course depends on. Done theatrically, with red ink and thumbprints, it will only get the letter ignored.