This should really stand out on the page and will typically be bigger than all other text on the document. As a minimum, you should include your full first name, and full surname.
If you wish, you can also include:
Titles (e.g. Miss, Dr, Prof, etc)
Applicable post-nominal letters (e.g. BSc, MA, PhD, etc)
Make sure that all other correspondence with the company can be clearly connected to the name you use here. If you go by a shortened version of your name, for example, you can either use that here or you include it in brackets after your full name to avoid any confusion when you sign your emails with it.
You should ideally include your full postal address.
221b Baker Street, London, NW1 6XE
If you’re uncomfortable giving your full address for some reason, be as specific as you can. You might include something like:
Baker Street, London
London, NW1 6XE
And if you’re applying for a role that would require you to relocate, you might include “Willing to relocate” next to your address to show that you’ve given this thought.
This should be the most reliable contact telephone number you can be reached on. Employers can (and do!) follow up by phone, so it’s important this is accurate and includes any necessary dialling codes.
If Sherlock were applying for a job outside of the UK, he would list it as:
+44 7987 654321
You can list both a landline number and mobile number if you want, but these days, it’s perfectly acceptable to only list a mobile number.
You should use a professional sounding email address – something as close to [yourname]@[emailprovider].com as possible.
If you currently use something different, it’s worth the effort to create a professional one – you can always set it up to forward to the one you check all the time. There can be a lot inferred about you from the email address you use, so make sure it’s representing you well.
Also remember that some email providers link a photo to your email account that is visible to recipients (Gmail is the biggest example of this) – so make sure that you’re using this as another place to create the right impression.