INI is literally just a programming language. So the same thing as .lua, .css, .cfg, etc. You can just select the file, hit F2, then rename the file extension to .ini instead of .txt. Now this isn't a fix-all for every single file type such as photos, videos, etc. This is ONLY for text files.
As for your game not loading when you paste it in, you probably aren't pasting it correctly.
[Sheriff Jacket]
Gender=Male
Hat=14:2
Glasses=9:1
Ear=0:0
Watch=0:0
Mask=101:1
Top=31:4
UpperSkin=5:1
Decal=1:1
UnderCoat=57:1
Pants=34:1
Shoes=54:2
Accessories=9:1
Armor=29:2
Parachute=49:1
The configuration above is one of my saved outfits. If the presets you are trying to paste into your wardrobe.ini do not look like the above, it is wrong. I'd possibly be able to help more if I got an RPH log. Seeing as this post is from almost 3 months ago however, I would hope you have figured it out. If not, feel free to reply!