how do i convert y=(x-3)^2-5 to standard form

I think you might mean  ax^2 + bx + c   form

y = ( x -3)^2 - 5         expand

y = (x-3) (x -3)  - 5

y = x^2 - 6x + 9 - 5     simplify

y = x^2 - 6x + 4  

Note....in "standard form," y is taken to  be 0......so......the equation becomes

x^2 - 6x + 4  = 0