There are two ways to change your SYNCbits password:
From the SYNCbits Panel
Go to https://my.syncbits.com and sign in with your current SYNCbits password. You'll find the "Change password" button there.
From the applications
On desktop versions of MoneyWiz, locate the SYNCbits menubar item at the top of the screen (Windows) or window (Mac) and find "Change password" there.
On mobile (iOS and Android) you'll find that option in MoneyWiz's Settings -> SYNCbits.
But I've forgotten my password!
Please see this article for guidance on what to do in this case.