@Singh, Rajendra Thanks for reaching out.
The standard logic app is deployed using the zip package. The zip package should contain all the workflows in the repo and the latest version of configuration files (parameters.json, connectors.json etc).
To answer your queries :
Can we deploy an individual workflow instead of replacing the whole Logic App? We just want to add a new workflow on a existing logic App.
As it is the zip deployment, so all the workflows are deployed again when you deploy using DevOps, ARM package etc. Unfortunately, there is no way to deploy only new workflow to your standard logic app.
Let me know if you have any queries or concerns.
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