Implementing ISO 9001 to only one department

Note:- Organization is at single Physical location do not have any sub-office or do not have any branch.

Answer:

In theory, ISO 9001 can apply to one department but such implementation will have too many constrains. You will need to consider the rest of the company as a customer basically, and you will still need to implement processes that already exist in the company for this one single department. This doesn't make too much sense since implementing the standard in this way will have very limited affect on the quality of the product and services and real customers, so I would suggest you to avoid it and implement the standard for entire organization because the level of effort will be pretty much the same.

For more information, see: How to define the scope of the QMS according to ISO 9001:2015 https://advisera.com/9001academy/knowledgebase/how-to-define-the-scope-of-the-qms-according-to-iso-90012015/