An expression of interest (EOI) is a declaration submitted through SkillSelect that you want to be considered for a skilled visa. Submitting an EOI is not the same as lodging a visa application. It places you in a pool of candidates ranked by their claimed points.
If you are invited from the pool, you then have 60 days to lodge the actual visa application and provide evidence for the claims you made. Only at that stage do you pay the visa charge and prove your points.