A non-functional requirement(NFR) is a requirement that specifies criteria that can be used to judge the operation of a system, rather than specific behaviours. 

For example, please check the following:

1. Backup – https://help.salesforce.com/s/articleView?id=000334121&type=1

 

 

3. Disaster Recovery – https://www.infallibletechie.com/2019/07/salesforce-disaster-recovery.html

 

4. Performance Testing – https://help.salesforce.com/s/articleView?id=000335652&type=1

 

5. Security – https://security.salesforce.com/