Managing a flow
Just like processes, a flow can be Active or Inactive. Once a flow is activated, it cannot be updated anymore, and to make changes, you need to create a new version of it.
In fact, a flow can be saved with a new version by clicking the Save As button on the upper-right corner of Flow Builder. You are able to create a brand new flow or another version of the same, so you can activate it when needed.
This is an example of a flow with more than one version and only one of them active:
Regarding distribution and places of execution, a flow can be distributed in the following ways:
A Lightning page using the standard flow component (Lightning App Builder)
A record quick action using the flow action type
The Lightning Console
The Utility bar or any Lightning app
By URL (see https://help.salesforce.com/articleView?id=flow_distribute_internal_url.htm&type=5)
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