With an upper case ‘A’. It's the name of a specific app. To avoid repetition of ‘NHS App’, you can use ‘the app’ where needed. When referring to something inside the NHS App, use ‘in’ the app, not ‘on or ‘with’ the app.
See also app.
When referring to the website at nhs.uk, use ‘the NHS website’ (lower case ‘website’) and give the url in lower case. However, if talking about NHS.UK as a programme, use capital letters.
Do not use a space between ‘NHS’ and ‘mail’ and, in general, avoid using ‘NHSmail2’. The current platform is ‘NHSmail’.
We use numerals (‘1’, ’2’, ‘3’) instead of spelling out numbers (‘one’, ‘two, ‘three’) because people find it easier to scan pages for numerals.
We do spell out numbers when we are using ‘one’ to mean ‘a’ or in phrases like ‘one or the other’.
It is OK to use numerals at the start of sentences and in headings.
For ordinal numbers, spell out first to ninth. After that use 10th, 11th and so on. Use full-sized letters after the number, not superscript. In tables, use numerals throughout.
For numbers over 999, use a comma for clarity, for example, ‘1,962’.
For numbers less than 1, use 0 before the decimal point, for example, ‘0.25’.
In general, write out ‘million’ or ‘billion’, for example: ‘£14 million’. If it is necessary to abbreviate, put ‘m’ or ‘bn’ immediately after the value, for example: ‘£14m’.
See also fractions, money and percentages