If you have changed your mind and now wish to withdraw your visa application then you have to complete a form for this. Note that removing the visa application from your ImmiAccount does not withdraw the application for the Australian visa be this a spouse visa or carer visa. You have to give written notice for this.
Note that you can withdraw the Australian visa application by advising them in writing before they have made a decision about your application. You are going to need to complete Form 1446 for this. Also note that your withdrawal notice has to include your name, date of birth and also your reference number. If there was more than one person over the age of 18 on the application form then they will also need to add their signature.
If you have applied online then you will have to attach the signed form to the account so that it becomes the written notice of your withdrawal of the visa application.