The reference list or bibliography at the end of your assignment is not included in your word count.
If you are using a footnote-based referencing format, the footnotes are also not included. If you are using an in-text based referencing format, such as Hull Harvard or APA, your in-text citations (the bits in brackets) are included.
There may, of course, be exceptions so you need to check your module handbook or check with your tutor to make sure.