She is Eddy's personal assistant. The character speaks with a strong Lancashire accent, exhibits a daft fashion sense, is emaciated like her brain (as stated by Patsy Stone), and acts in an apparently foolish manner.
She is unable to remember the names of common objects or understand basic concepts. Frequent comedic dialogue between Edina and Bubble involves Edina dragging vital information out of her unresponsive PA. Bubble's function in the PR company is simply to flatter Edina's vanity by comparison.