Hi FlashMTU1965,
Thanks for using Apple Support Communities. We understand you're experiencing an issue with an email password. We're happy to get you pointed in the right direction.
If you're only experiencing this with the one account, you can remove and re-add those using the password you're using on the iPad. See how here:
Add or remove email accounts in Mail on Mac
Add an email account to your iPhone, iPad, or iPod touch
If this continues, or you're unable to remove/add that account reach out to Microsoft Support for further assistance. You can see how to get started with them here: Microsoft Support
Thanks