There is no such thing as a UK death certificate
This question highlights a common misconception that the UK is more or less equivalent to England, but for genealogical purposes it is important to recognize the distinction.
In 1908, the UK was the United Kingdom of Great Britain and Ireland, thus comprised of 4 countries: England, Wales, Scotland, and Ireland. Of course, after Irish independence in 1922, only Northern Ireland remained part of the UK.
The relevance for family history? Civil registration in these countries was regulated by these countries separately, with the notable exception that England and Wales were administered as a single jurisdiction. The UK does not issue death certificates.
Therefore, when asking for what information a UK death certificate contained in 1908, do you mean a certificate from England, Wales, Scotland, or Ireland?
Scotland
A 1908 death certificate from Scotland has the following columns:
- Number [in Register]
- Name and Surname, Rank or Profession, and whether Single, Married, or Widowed
- When and Where Died
- Sex
- Age
- Name, Surname, & Rank or Profession of Father, and Name, and Maiden Surname of Mother
- Cause of Death, Duration of Disease, and Medical Attendant by whom certified
- Signature & Qualification of Informant, and Residence, if out of the House in which the Death occurred
- When and where Registered, and Signature of Registrar
An example Scotland death entry from 1908:
Image obtained from ScotlandsPeople.
Ireland
A 1908 death certificate from Ireland has the following columns:
- Number [in Register]
- Date and Place of Death
- Name and Surname
- Sex
- Condition [as to Marriage]
- Age last Birthday
- Rank, Profession, or Occupation
- Certified Cause of Death and Duration of Illness
- Signature, Qualification and Residence of Informant
- When Registered
- Signature of Registrar
An example Ireland death entry from 1912 (it was the same format in 1908):
Image obtained from the Irish Genealogy Toolkit website
England & Wales
The information contained on a death certificate from England and Wales has been given in other answers, but I will include it here as well for completeness. A 1908 death certificate from England and Wales has the following columns:
- Number [in Register]
- When and Where died
- Name and Surname
- Sex
- Age
- Occupation
- Cause of Death
- Signature, Description and Residence of Informant
- When Registered
- Signature of Registrar
An example England death entry from 1907 (it was the same format in 1908):
Image obtained from the Bob Anderson's Family History website
As you can see, there are notable differences between the information contained on death certificates from each of the countries of the UK. The Scottish certificates contain the most useful genealogical information – parents' name and occupations, as well as marital status. Irish certificates are similar to those from England and Wales but they also contain a column for marital status.
Also keep in mind that death records were entries made in registers very much like you might search when you are looking for a baptism or burial. A death certificate (a certified entry of death) is only made when you request it – before that, it is simply an entry in a death register. The examples from Scotland and Ireland above are thus not death certificates per se, they are simply excerpts of pages from the death register. In England and Wales the public is not allowed to access the death registers, which is why ordering a certified copy of the death entry is our only means to access the information contained in the death registers.