...

Non-functional requirement (NFR) is a requirement that specifies criteria that can be used to judge the operation of a system, rather than specific behaviors.
They are contrasted with functional requirements that define specific behavior or functions. 

Wikipedia: https://en.wikipedia.org/wiki/Non-functional_requirement

...

Non-functional requirements are criteria to judge that the system performs its functions the right way. For instance, the max downloaded file size is 1 Gb, it should be downloaded within 12 seconds, etc.

Examples

• Scalability
  It tells what amount of data or number of users the system should be able to process.
  
  
• Performance
  How fast a certain system functions should be performed.
  
  
• Fault tolerance
  How fast the system should be restored in case of an unexpected issue.

...

The NFRs could be collected during a meeting with Customer / Hosting providers or by sending the following spreadsheet template: 

https://docs.google.com/spreadsheets/d/1vhszxQbrz527-mSFsCuTVGdjfHiA3JvvZ4l7RS7loc01vxawUPFKYVf8Ekqr6gGDo_kA8VJlgqBEmLWbntXSgIo/edit?usp=sharing

The template contains major NFRs that should be collected along with questions helping to do this. 

Once NFRs are collected, they should be put to the target spreadsheet:

https://docs.google.com/spreadsheets/d/1oa5PnM9HqbKQl1lAe08aKojz29Go_-amQCNiMzwPnZc/edit#gid=01x7_yoJNtx_S90iVowrJB64oJt87nsBFJIauyYp87MPc/edit?usp=sharing

It is recommended to make sure:

...

NFRs for all product areas should be added to the following spreadsheet:

https://docs.google.com/spreadsheets/d/1oa5PnM9HqbKQl1lAe08aKojz29Go_-amQCNiMzwPnZc/edit#gid=01x7_yoJNtx_S90iVowrJB64oJt87nsBFJIauyYp87MPc/edit?usp=sharing

All Folio architects and developers can leverage them then for the product needs.

...