Evidencing version control

Answer: No, a version number does not have to remain on the actual document.

2. Does a version number have to be on the documents at all as long as you have version history showing under the Standard Documents under your QMS?

Answer: No, please check ISO 9001:2015 clause 7.5.3.2 c) about version control. You need to figure out how you will identify documents so that the people who need to use them know there is a change, as well as ensure that if a user has two versions of a document, they know which is the latest version to use. So, how does your QMS guarantee that users are aware that they are using the latest version? Some organizations instead of a version number use a date, others use a name, others only control digital versions and whenever a document is printed it has a warning to users saying that they don’t control documentation on paper.

The followin g material will provide you more information:
ISO 9001 – Some Tips to make Document Control more useful for your QMS - https://advisera.com/9001academy/blog/2014/05/20/tips-make-document-control-useful-qms/
You can enroll for free at ISO 9001:2015 Internal Auditor Course - https://advisera.com/training/iso-9001-internal-auditor-course/
Book - Discover ISO 9001:2015 Through Practical Examples - https://advisera.com/books/discover-iso-9001-2015-through-practical-examples/