Has the firm given you an example or any guidance on how to write it? A lot of firms do so that your writing is going to be fairly consistent with other vacation scheme students. If they have given this to you, then always follow their structure and guidance first.
If they haven't provided anything to you, then something like the following length would be appropriate:
Jess studied Economics and Social Studies at the University of Manchester, graduating with a first-class honours in 2004. Since then, she has worked in the Early Careers sector for a range of companies across the legal, professional services, investment and FMCG sectors. Before her career, Jess was a Chef, working in various pubs and also as a Chalet host in the French Alps. She continues to love both cooking and skiing, as well as trying to keep up with her hyperactive dog, Dennis. Jess looks forward to understanding more about the firm's clients during the vacation scheme, as well as learning more about the firm's diversity initiatives.
It might be that they want you to write in the first person though - I have just written in the third person due to habit!
Ultimately try to include:
- Key and relevant facts about your background
- 1 or 2 key achievements (I included my degree classification)
- Something about your interests - what you do outside of work/study
- Something interesting about you - maybe something more unique (why I always throw in the fact I was a chef)
- If you feel comfortable doing so, something slightly light-hearted or that could be a conversation starter (why I reference my dog. Dennis!).
- Adding some kind of reference as to what you hope to gain by attending the scheme