Before we begin, there are several things that you need to know before filling out tags.

• You need a space after tags=, or else it won’t work.
  
• Use lowercase characters ONLY, no uppercase, or special symbols.
  
• Use commas to separate tags.

Below is the list of tags that you can use for the workshop. Case sensitive:

• voice
  
• soldier customization
  
• soldier class
  
• facility
  
• voice
  
• ui
  
• item
  
• weapon
  
• map
  
• alien
  
• gameplay
  
• war of the chosen

This is what it should look like:

1. Go to XCOM 2 SDK/XCOMGame/Mods/YourMod and open YourMod.XCOMMod with Notepad, or any text editor.
   
2. Go down until you see tags=
   
3. Fill it out with the appropriate tags so that other people can find it.
   
4. Save the text document, and publish your mod. You should see now that you have tags, so other people can find your mod.

Thanks to Future Null Infinity for helping me figure this out!

Apparently there's a bug in Modbuddy for both Vanilla and WotC versions that allows you to put tags in the description of the mod. This is a lazier way to add tags to your mods without having to save to a text file or remembering what tags you've added.

The best part is, you don't have to worry about if the tags will disappear when you compile the mod again. Just follow this one weird trick!

To do this trick, you just have to open the properties of the project, or if you got the pop up box asking for the mod name and the description to the mod, add the following:
where <wtagN> is the name of the workshop tag that you want!

Example:

If done right, it should look like this:



Once you save your project, and then compile, the tags should stick forever.