Hi @davidsteve For more information: 

MFA is the additional prompting that helps us confirm you are who you say you are during sign on.
SSO is a single sign on, where one program can be signed into then a second program is opened without login prompt. 

If you want to turn off SSO, we ask that you contact support so we can confirm that you are contact they are speaking with and they require a reason for why you are requesting it be turned off.  (MFA can be turned off by the Primary by logging into MyAccount).

Here is a knowledge base with more information : Common questions about ProSeries Multi-Year Access - Single Sign On (SSO)