Switch to the right business (if you have more)

Click on ⚙️ Settings and go to the My Team

app: Click on your user name or e-mail
website: In the upper right corner click on the user name or e-mail

A new screen appears

Your role is set as an Owner or Employee

Now you can alter your user name or e-mail address

Your password can be changed only on the website when you edit your team member settings

You can add a signature which will appear on your invoice