Wondering how people make those edits of booth models

[VrGaming69]

I have been seeing a lot of these the last while and i have been wondering how people adjust the body shape like that. Can anyone help me (and maybe future people wondering) out with this?
Example images:

[Gronar]

Bump

[avatarofcorn]

You change the scale of the bones in the avatar's Armature. Be warned that fitting outfits will get troublesome. If you use MA or VRCFury, there's a chance outfits will be fitted wrongly and you'll have do it the old way by dragging and dropping the outfit bones, then scaling those up. Keep notes on which bones you scaled so you know which to adjust!

[avatarofcorn]

For your reference, you can look at how they did it in here:

桔梗大人プリセット　Kikyo big Preset - 大人化計画+プリセット屋 - BOOTH

！ジェスチャーが正しく動作しない場合がありますが、元商品の桔梗側の問題で現在解決策模索中です！ 本製品は桔梗が無いと正常に作動しません 下URLからお買い求めください https://ponderogen.booth.pm/items/3681787 この商品の主コンテンツはパラメーター調整された（改変された）のシーンデータとなります。 unity packageが入っていますのでunityへインポートしてご使用ください。 主な変更点（詳細は商品画像部分に有ります） ・体型の成長 ・顔の成長、それに伴う一部表情調整

(booth.pm)

Big and Chibi Presets for: Kikyo, Chiffon, Manuka, Moe, Selestia, Shinra

Good luck!

[VrGaming69]

ohh ok
thanks