For an SVN or Git managed project, a tag is a read-only copy that records the current state of the project at the point of time the tag is created.
When working in a tag, you can make changes to your project items, but you will be unable to permanently save your changes to a Job unless you copy the Job to a branch or the trunk/master. For how to copy a Job to a branch, see How to copy a Job to a branch.
You can create a tag for a project either in Talend Studio or in Talend Administration Center.
All branches/tags are visible for all projects on the same Git repository. Therefore, if you create some tags for one project, all other projects on the same Git repository will have the same list.
To create a tag for a project from the trunk in Talend Studio, do the following:
Close all open editors in the design workspace before trying to create a tag. Otherwise, a warning message will appear prompting you to close all open editors.
Open the remote project for which you want to create a tag.
Click the icon at the upper right corner of the Repository tree view to open the [Branch management] dialog box.
Click the Create a tag button, and in the next dialog box select trunk from the tag's source list, enter a tag name, and click OK.
In the [Confirm] dialog box, click OK to confirm your tag creation.
Creating a tag may take some time. When done, the tag you created will appear on the tags list in the [Branch management] dialog box and you can switch to it by following the steps in How to switch between branches.
For how to create a tag in Talend Administration Center, see Talend Administration Center User Guide.