@jovangelderoña  You can do it either way .... You can create your own immiaccount or you can create an immiaccount for your husband.
 
But I think its just better to create your own immaccount so that if something went wrong you can ask for immigration technical assistance.
 
Once you create your immiaccount you can lodge a visa application in behalf of your husband. You will be issued a reference number for that application.
You or your husband  have to complete that online form, submit , and pay for the lodging fee
Once this is paid you  can now fill up the form "Sponsorship for a partner to migrate to Australia"
When filling up the sponsorship form you  will then be ask o link that sponsorship form with the partner visa application reference number. ( You will not be able to this until you made the payment)
When both the Migration to Australia by a partner form and the Sponsorship form is completed. You can now start uploading your documents
You will notice that you already have an  HAP ID for medical
 
Yes both of you can update that single immiaccount .
 I just dont know what will happen if there is a multiple login on the same immiaccount?