Use the following steps to move a Marketo form submit button:
Step 1: Edit the landing page that holds the form you would like to adjust.
Step 2: Drag on a Custom HTML block from the right-hand side.
Step 3: Copy and paste one of the following codes into the Custom HTML block:
Note: A negative value moves the button left and a positive value moves it right.
Note: The higher the number, the farther down the button will move.
Step 4: Re-approve the landing page and make adjustments as needed.
Source: Marketo Community