You can edit your character's description at any time with the /editdesc chat command. This will open a NUI window for editing your description.
Note that because of a limitation with the game's NUI system, text won't wrap onto the next line in the editor which can make editing large descriptions a less than desirable experience. Your descriptions will display correctly in the examine window once saved, and so it's important that you don't manually add line breaks into your description to make it display nicely inside the editor, otherwise you will have odd line breaks in the middle of paragraphs and sentences in your final description.
It's recommended that you have a copy of your character's current description saved outside the game in a .txt file.
When you need to edit your character's description, use the Clear button to delete your current description, then copy paste your new description from your .txt file into the editor in-game.
Use the Preview button to preview how the description will look in-game to others.
When you are finished editing your description, use the Save button to save your character's description
You can change your voiceset in game at any time with /setvoiceset #.
Example:
/setvoiceset 419
Voiceset numbers can be found in soundset.2da.