Question: I want to change release names like `V.1.0.00` for manual release in Continuous Delivery of Azure DevOps but i can't able to delete or change the naming without this `$(rev:r)`, how can I use a custom name?

Default Name: `Release- $(rev:r)`

Required Name: `V.1.0.0`

Answer: 
You can change the naming scheme by editing the release name format mask.

When specifying the format mask, you can use the pre-defined variables mentioned in this official [document](https://learn.microsoft.com/en-us/azure/devops/pipelines/release/index?view=azure-devops#how-do-i-manage-the-names-for-new-releases) or custom variable -- the value of a global configuration property defined in the release pipeline.

But for your issue ,as far as I know, no pre-defined variables can be displayed like V1.0.0 as release name.
You can't. release name must be a **unique** name, therefore Azure DevOps requires you to put `$(rev:r)` in the name, because it's adding a incremental number for each release.

Another option is to use `$(Build.BuildNumber)` or `$(Release.ReleaseId)` that are also unique but is not will solve your issue.