Login your Amazon Seller Central account.
Hover your mouse to “Settings” located on the top right and select “User Permissions” in the drop-down menu.
Type in the Name (Sellvia) and Email address (firstname.lastname@example.org) in the blank field and click “Send Invitation”.
Once the invited user has accepted the invite, the name will show up in the “Current User” area.
By then, you can manage the user’s access to your account by clicking the “Manage Permissions” button.
By default, the user doesn’t have any permissions yet until you assign them one. You need to give permissions by clicking all available View&Edit buttons.
Click Continue and then click Continue once again. You are done!