First, make sure that you are choosing an individual you trust to view your bank account. Then, follow some simple instructions!
When Login to your bank account
For Wells Fargo, it's as simple as logging in, as well as adding an Account Access Manager. Then, select the "Guest Users" tab
Finally, add the information for your new guest user.
Chase and other banks have similar access
⇒Chase Bank : Go to "Account Management" at the top, then to "Add Authorized user"