Q:

What is the procedure to add description to a newly created tag?

After getting enough reps (I am not sure how much), one can create tags.
Questions:

What is the procedure to add small description to the tag?

What is the procedure to make synonyms? Eg: EU and European union.

Thanks in advance for your time.

A:

You can create tags on this site after reaching 150 reputation. You can do this simply by adding the new tag to a question - it will be created automatically.
To add a description to your tag, you can visit the tag's 'About' page. In your case, you have created the chinese-communist-party tag, and you can find this tag's information here. Any registered user can suggest edits to this information, and trusted users (4k rep) can have edits approved automatically.
Ideally, a tag should have a tag wiki and usage guidance. Details on what these should contain can be found here.
In order to propose synonyms to a tag, users require the 'create tag synonyms' privilege which is granted at 1,250 rep. They also require an answer score of 5 on the tag. These are then voted on by other users with the requisite answer score. You can also make a post on meta to suggest a synonym if you're not sure, or don't have the requirements to propose a tag synonym, after which a mod may implement your suggestion.

